Search

Synonyms for un substantial
adj flimsy

fragile

frail

thin

Antonyms for un substantial

undeniable

well-founded

Synonyms
adj unreal

imaginary

unbelievable

vaporous

visionary

Antonyms

undeniable

well-founded

Synonyms
adj lacking substance

unreal
aerial
diaphanous

ethereal
filigree
imaginary

inane
shadowy
visionary

Antonyms

undeniable

well-founded

Synonyms
adj illusory, romantic

whimsical
pensive
introspective
gentle
otherworldly
fanciful
utopian
quixotic
nightmarish
abstracted

astral
calming
chimerical
daydreaming
excellent
fantastic
idealistic
imaginary
immaterial
impractical

intangible
marvelous
misty
musing
mythical
out of this world
preoccupied
shadowy
soothing
speculative

unreal
unsubstantial
vague
visionary
phantasmagoric
introvertive
lulling
phantasmagorical
relaxing

Antonyms

real
horrible

terrible
unromantic

Synonyms
adj fruitless, ineffective

flat
worthless
meaningless
hollow
devoid
idle
barren
petty
silly
dead
aimless

banal
cheap
deadpan
dishonest
dumb
expressionless
fatuous
frivolous
futile
ignorant
inane

ineffectual
inexpressive
insincere
insipid
jejune
nugatory
otiose
paltry
purposeless
senseless
trivial

unintelligent
unreal
unsatisfactory
unsubstantial
vacuous
vain
valueless
vapid

Antonyms

valuable
worthwhile
meaningful
useful
filled
productive

entire
replete
satisfied
abundant
copious
fruitful

sufficient
raised
full
complete
sated
effective

Synonyms
adj delicate, heavenly

celestial
intangible
exquisite
ghostly
airy
sublime
aerial
dainty

divine
empyrean
fairy
filmy
fine
gaseous
gossamer
impalpable

insubstantial
light
rarefied
refined
spiritual
subtle
supernal
tenuous

unearthly
unsubstantial
unworldly
vaporous
empyreal
vapory

Antonyms

indelicate
poor

earthly
worldly

Synonyms
adj not strong; light, thin

shaky
decrepit
insubstantial
tacky
rickety
feeble
shallow
gossamer

wobbly
frail
slight
defective
delicate
diaphanous
fragile
gauzy

inadequate
infirm
meager
sheer
slapdash
sleazy
superficial
transparent

unsound
unsubstantial
weak
chiffon
cut-rate
house of cards
papery
rinkydink

Antonyms

healthy
sturdy
convincing
plausible
strong

sound
thick
firm
heavy
solid

substantial
tough
reasonable
serious

Synonyms
adj unconvincing, implausible

baseless
lame
groundless
thin
feeble
frivolous
poor
trifling
assailable

contemptible
fallacious
illogical
improbable
inadequate
inane
inconceivable
incredible
inept

puerile
superficial
transparent
trivial
unbelievable
unreasonable
unsatisfactory
unsubstantial
weak

wishful
weakly
false
controvertible
ungrounded
unpersuasive

Antonyms

efficient
sturdy
convincing
plausible
able

strong
solid
firm
heavy
substantial

thick
tough
reasonable
serious

Synonyms
adj breakable, weak

slim
fragile
slender
sickly
decrepit
thin
infirm
feeble

vulnerable
tender
brittle
flimsy
slight
dainty
delicate
fishy

insubstantial
puny
sad
tenuous
unsound
unsubstantial
wishy-washy
wispy

frangible
fracturable
shatterable
shattery
wimpy

Antonyms

healthy
unbreakable
firm
strong

fat
hearty
solid
sound

rough
tough
heavy
thick

Synonyms
adj hopeless, pointless

fruitless
worthless
impractical
ineffective
vain
insufficient
hollow
ineffectual
useless
unsuccessful
unproductive

unprofitable
trivial
abortive
barren
bootless
delusive
empty
exhausted
forlorn
idle
impracticable

nugatory
otiose
sterile
trifling
unavailing
unimportant
unneeded
unreal
unsatisfactory
unsubstantial
valueless

in vain
no dice
on a treadmill
out the window
profitless
resultless
to no avail
to no effect
to no purpose
save one’s breath

Antonyms

fruitful
productive
profitable
successful

useful
valuable
worthwhile
helpful

effective
hopeful

Synonyms
adj not making sense

incorrect
unscientific
irrational
senseless
unreasonable
preposterous
groundless
untenable
absurd
implausible
irrelevant

inconsistent
cockeyed
fallacious
fatuous
faulty
hollow
inconclusive
incongruous
invalid
mad
meaningless

nutty
off the wall
screwy
specious
spurious
unconnected
unsound
unsubstantial
wacky
inconsequent
sophistic

unproved
false
casuistic
not following
self-contradictory
sophistical
without basis
without foundation

Antonyms

logical
rational
sensible

wise
meaningful
correct

right
true
reasonable

Synonyms
adj fictitious, invented

whimsical
fantastic
abstract
fictional
unreal
fanciful
hypothetical
imagined
theoretical
ideal
visionary

apocryphal
assumed
chimerical
deceptive
delusive
dreamy
fabulous
hallucinatory
illusive
illusory
imaginative

legendary
made-up
mythological
nonexistent
notional
phantasmal
phantasmic
quixotic
shadowy
spectral
supposed

supposititious
trumped up
unsubstantial
apparitional
dreamed-up
dreamlike
fancied
figmental
fool’s paradise

Antonyms

factual
real
existing
ordinary

proven
practical
genuine
physical

substantial
true

Synonyms
adj not existing in physical form

incorporeal
aerial
airy
celestial
dreamy
ethereal
ghostly
heavenly
impalpable

incorporate
insensible
intangible
metaphysical
psychic
shadowy
spectral
spiritual
subjective

supernatural
unearthly
unsubstantial
unworldly
bodiless
disembodied
imponderable
nonphysical
nonmaterial

dreamlike
apparitional
asomatous
disbodied
discarnate
spiritlike
unembodied
unfleshly
wraithlike

Antonyms

meaningful
relevant
bodily
real

essential
important
material
substantial

physical
solid

Synonyms
adj not likely

unbelievable
incredible
unreasonable
dubious
farfetched
improbable
flimsy

impossible
inconceivable
unconvincing
doubtful
far out
fishy
obscure

problematic
puzzling
suspect
thin
too much
unsubstantial
weak

for the birds
full of holes
reachy
won’t hold water
won’t wash

Antonyms

believable
credible
plausible
possible

tenable
likely
convincing
realistic

reasonable
possibly
probably

Synonyms
adj not likely

implausible
rare
unbelievable
fanciful
unlikely
doubtful

dubious
far-fetched
flimsy
iffy
inconceivable
questionable

slim
uncertain
unconvincing
unimaginable
unsubstantial
weak

hundred-to-one
not expected
outside chance
slim and none
unheard of

Antonyms

believable
likely
plausible
real

ostensible
possible
probable
tenable

probably
ordinary

Synonyms
adj beyond reason, belief

unimaginable
incredible
improbable
unbelievable
unheard-of
strange
mind-boggling

implausible
impossible
extraordinary
unthinkable
fantastic
phony
rare

staggering
thin
unconvincing
unlikely
unsubstantial
weak
imcomprehensible

incogitable
insupposable
reachy
unknowable
won’t fly
won’t wash

Antonyms

believable
credible
plausible
possible
tenable

likely
usual
conceivable
fathomable
imaginable

familiar
normal
common
reasonable

Synonyms
adj beyond belief

unbelievable
unimaginable
preposterous
improbable
ridiculous
absurd
inconceivable

far-fetched
fishy
flimsy
implausible
impossible
out of the question
outlandish

phony
questionable
suspect
thin
unconvincing
unsubstantial
untenable

unthinkable
incogitable
insupposable
rings phony

Antonyms

believable
plausible
imaginable
sensible

credible
possible
tenable
terrible

reasonable
realistic
bad
poor

Synonyms
adj sick, weak

insecure
ill
anemic
decrepit
unstable
frail
ailing

feeble
debilitated
delicate
failing
faint
flimsy
fragile

halting
irresolute
lame
shaky
unsound
unsubstantial
vacillating

wavering
wobbly
anile
enfeebled
faltering
laid low
sensile

Antonyms

healthy
robust

sound
strong

firm
hearty

Synonyms
adj not important; of no consequence

paltry
pointless
minuscule
senseless
inconsequential
meaningless
unimportant
infinitesimal
negligible

minor
irrelevant
meager
trivial
minimal
casual
immaterial
lesser
light

lightweight
little
minute
nondescript
nonessential
nugatory
petty
scanty
secondary

small
trifling
unsubstantial
inappreciable
inconsiderable
minim
not worth mentioning
purportless

Antonyms

meaningful
sensible
huge
useful
valuable

worthwhile
relevant
large
consequential
important

significant
substantial
big
major

Synonyms
adj weak, imaginary

illusory
flimsy
unreal
fanciful
tenuous
puny
unsubstantial
aerial

airy
chimerical
decrepit
ephemeral
feeble
fly-by-night
fragile
frail

idle
immaterial
incorporeal
infirm
intangible
metaphysical
petty
poor

slender
slight
thin
unsound
imponderable
false
too little too late

Antonyms

real
genuine

strong
substantial

thick
serious

Synonyms
adj indefinite, obscured

unreal
ethereal
hypothetical
slight
abstract
impalpable
imponderable
abstruse

airy
dim
elusive
evanescent
evasive
imperceptible
incorporeal
indeterminate

insensible
invisible
rare
shadowy
slender
uncertain
unsubstantial
unsure

vague
inappreciable
unobservable
eluding
evading
unapparent

Antonyms

factual
real
obvious

perceptible
tangible
definite

palpable

Synonyms
adj flimsy

cheap
defective
insubstantial

makeshift
ramshackle
rickety

shoddy
slipshod
unsound

unsubstantial
jerry-rigged
junky

Synonyms
adj smaller, inferior

limited
lower
negative
lesser
subordinate
minus

minor
secondary
beneath
deficient
depressed
lacking

reduced
shorter
unsubstantial
without
fewer
declined

diminished
excepting
not as great
shortened
slighter
subtracting

Antonyms

higher
greater
more

important
superior
major

bigger

Synonyms
adj not heavy

agile
slight
buoyant
fluffy
loose
slender
delicate
easy
lightweight
small
airy
thin
sheer

petty
portable
little
flimsy
dainty
floating
trifling
atmospheric
crumbly
downy
effervescent
ethereal
feathery

filmy
friable
frothy
graceful
inconsequential
insubstantial
lithe
meager
nimble
porous
sandy
spongy
sprightly

trivial
unsubstantial
weightless
featherweight
floatable
gossamery
imponderous
light-footed
sylphlike
tissuelike
unheavy

Antonyms

large
useful
clumsy
dusky
big
important
fat
thick
heavy
coarse

rough
strict
strong
oppressive
significant
black
dark
darkened
dim
gloomy

obscure
brunette
weighted
difficult
laborious
grave
serious
solemn

Synonyms
adj small in amount, content

slight
faint
weak
tiny
gentle
mild
thin
sparse
moderate
soft
casual

wee
scanty
restricted
minute
minuscule
minor
trifling
digestible
fractional
fragmentary
frivolous

frugal
inadequate
inconsequential
indistinct
insignificant
insufficient
modest
puny
superficial
trivial
unimportant

unsubstantial
inconsiderable
shoestring
hardly any
hardly enough
not many
not much
not rich

Antonyms

large
brave
huge
dusky
big
great
significant
fat
thick
heavy
loud

strong
bold
firm
concentrated
rough
violent
wild
harsh
important
black
dark

darkened
dim
gloomy
obscure
brunette
weighted
difficult
laborious
grave
serious
solemn

Synonyms
adj not stiff; weak

supple
listless
soft
flabby
bending
plastic
wearied
debilitated
weakened
tired

exhausted
relaxed
loose
flimsy
spent
yielding
drooping
floppy
languishing
enervated

limber
slack
droopy
ductile
feeble
flaccid
flexible
impressible
infirm
languid

lax
lethargic
pliable
pliant
spiritless
unsubstantial
worn out
flexuous

Antonyms

rigid
restored
animated
lively
taut
unbending
hard

firm
straight
stiff
invigorated
active
energized
strong

activated
fresh
refreshed
saved
tight
solid
inflexible

Synonyms
adj not physical; without physical presence

mystical
spiritual
abstract
esoteric
philosophical
supernatural
abstruse
theoretical
deep
difficult
eternal

fundamental
high-flown
ideal
immaterial
impalpable
incorporeal
insubstantial
intangible
intellectual
preternatural
profound

recondite
superhuman
superior
transcendental
unearthly
universal
unreal
unsubstantial
bodiless
nonphysical
numinous

discarnate
jesuitic
nonmaterial
oversubtle
supermundane
suprahuman
supramundane
supranatural
unfleshly
unphysical

Antonyms

factual
real
obvious

objective
physical
concrete

material
solid
substantial

Synonyms
adj fictional, not real

absent
vacant
negative
tenuous
airy
baseless
blank
chimerical
dead
defunct
departed
dreamy

empty
ethereal
extinct
flimsy
gone
groundless
hypothetical
illusory
imaginary
imagined
immaterial
insubstantial

legendary
lost
missing
mythical
null
null and void
shadowy
unreal
unsubstantial
vague
vaporous
void

hallucinatory
imponderable
dreamlike
extinguished
fancied
few and far between
gossamery
passed away
passed on
perished
ungrounded
without foundation

Antonyms

existing
real

actual
existent

true

Synonyms
adj light in color or effect

pasty
gray
poor
dim
blanched
faint
haggard
thin
sick
faded

white
wan
sallow
dull
anemic
ashen
bloodless
cadaverous
colorless
feeble

ghastly
inadequate
ineffective
ineffectual
insubstantial
livid
lurid
pallid
sickly
spectral

unsubstantial
washed-out
waxen
weak
ashy
deathlike
bleached
doughy
waxlike
whitish

Antonyms

flushed
healthy
intelligent
strong
happy
bright

clear
distinct
light
smart
colored
heavy

dark
colorful
glowing
radiant

Synonyms
adj small, insignificant

paltry
measly
inconsequential
tiny
frail
trivial
feeble
diminutive
fragile
inferior
infirm

little
minor
niggling
nothing
peanut
petty
picayune
piddling
runt
stunted
trifling

two-bit
underfed
undeveloped
unsound
unsubstantial
weak
wee
worthless
zero
zilch
weakly

undersized
half-pint
peewee
pint-sized
shrimp
small time
small-fry
unconsequential

Antonyms

giant
huge
large

important
significant
strong

big

Synonyms
adj disreputable

seedy
trashy
sordid
tacky
base

broken-down
cheap
common
dilapidated
flimsy

limp
low
mean
paltry
poor

run-down
shabby
shoddy
squalid
unsubstantial

Antonyms

reputable
fine

good
nice

respectable

Synonyms
adj unreasonable

thin
flimsy
excessive
implausible

improbable
inconceivable
incredible
too much

unbelievable
unconvincing
unfair
unjust

unsubstantial

Antonyms

diluted
watery
intelligent
unfriendly
unsociable

sensible
wise
attenuated
slight
loose

uncrowded
smart
clear
reasonable

Synonyms
adj transparent, fine

wispy
slim
flimsy
delicate
translucent
sheer

slight
attenuate
rarefied
refined
diaphanous
filmy

gossamer
permeable
rare
subtle
tenuous
unsubstantial

see-through
paper-thin
attenuated
subtile
wafer-thin

Antonyms

inflated
obese
efficient
heavy

strong
thick
dense
fat

solid
concentrated
undiluted

Synonyms
adj deficient, weak

poor
flat
shallow
meager
flimsy
sparse
thick
transparent
skimpy

slight
diluted
lame
scattered
scant
feeble
implausible
improbable
inadequate

inconceivable
incredible
insubstantial
insufficient
questionable
scanty
scarce
sketchy
superficial

unbelievable
unconvincing
unsubstantial
untenable
vapid
stretched
unpersuasive
weak-kneed

Antonyms

adequate
sufficient
intelligent
inflated
obese
efficient

strong
substantial
full
reasonable
concentrated
dense

fat
heavy
solid
undiluted

Synonyms
adj beyond the imagination

unimaginable
incredible
preposterous
astonishing
improbable
outlandish
implausible
impossible
inconceivable
unthinkable
too much

cockeyed
doubtful
dubious
far-fetched
fishy
flaky
flimsy
harebrained
kooky
phony
questionable

reaching
scatterbrained
screwy
staggering
suspect
thick
thin
unconvincing
unsubstantial
weak
beyond belief

cockamamie
for the birds
full of holes
incogitable
lamebrained
open to doubt
past belief
won’t hold water
won’t wash

Antonyms

believable
imaginable
credible
plausible

possible
tenable
likely
conceivable

real
reasonable

Synonyms
adj fake, make-believe; hypothetical

unbelievable
immaterial
illusory
fanciful
hallucinatory
unsubstantial
artificial
insubstantial
aerial
chimerical
delusive

fabled
fabulous
fictitious
ideal
imaginary
imagined
impalpable
insincere
intangible
legendary
misleading

mock
mythical
nebulous
nonexistent
ostensible
pretended
romantic
seeming
sham
theoretical
visionary

fictive
invented
notional
phantasmagoric
suppositious
supposititious
false
dreamlike
figmental
reachy
storybook

Antonyms

real

authentic

genuine

Synonyms
adj not well; flimsy

incorrect
illogical
erroneous
unhealthy
defective
insecure
fragile
unsafe
inaccurate
shaky
unstable
insane

unreliable
faulty
unbalanced
ailing
crazed
dangerous
decrepit
delicate
demented
deranged
diseased
fallacious

frail
ill
incongruous
infirm
insubstantial
invalid
lunatic
mad
rickety
specious
unhinged
unsteady

unsubstantial
unwell
weak
wobbly
tottering
false
flawed
in poor health
not solid
unbacked

Antonyms

rational
valid
honest
reliable
healthy
protected
stable
sane
correct

right
true
reasonable
accurate
just
strong
well
perfect
certain

secure
sure
safe
sound
firm
steady
balanced

Synonyms
adj not strong

shaky
uncertain
hesitant
weakened
powerless
fragile
anemic
sickly
wobbly
frail
sluggish
feeble
unsteady

debilitated
decrepit
delicate
effete
enervated
exhausted
faint
flaccid
flimsy
infirm
insubstantial
irresolute
lackadaisical

languid
limp
makeshift
prostrate
puny
rickety
rocky
rotten
senile
spent
spindly
supine
tender

torpid
undependable
unsound
unsubstantial
wasted
wavering
languorous
weakly
forceless
impuissant
out of gas

Antonyms

unwavering
powerful
unbreakable
healthy
stable
potent
brave
confident
noisy
capable

sufficient
guarded
protected
firm
steady
certain
sure
definite
active
strong

able
hearty
bold
loud
fit
safe
secure
concentrated
thick
unshaky

Synonyms
adj deficient, feeble

poor
limited
inept
lacking
inadequate
shaky
ineffective
ineffectual
thin
small
immature
slim

incomplete
faulty
flabby
flimsy
green
handicapped
hollow
implausible
impotent
improbable
incompetent
inconceivable

inconclusive
incredible
invalid
lame
pathetic
raw
shallow
slight
spineless
substandard
thick
unbelievable

unconvincing
unprepared
unqualified
unsatisfactory
unsubstantial
unsure
untrained
wanting
forceless

Antonyms

adequate
sufficient
competent
enough
potent
brave
confident

noisy
capable
guarded
protected
strong
able
effective

firm
bold
loud
fit
safe
secure
concentrated

Synonyms
adj incorrect

untrue
inaccurate
mistaken
unsound
bad
erroneous
awry
amiss
misguided
erring
out
askew

astray
at fault
defective
erratic
fallacious
faulty
inexact
out of commission
out of order
perverse
rotten
specious

spurious
unsatisfactory
unsubstantial
wide
counterfactual
false
miscalculated
fluffed
misconstrued
mishandled
goofed
in error

misfigured
not precise
not right
not working
off-target
on the wrong track
out of line
sophistical
ungrounded

Antonyms

honest
valid
OK
moral
acceptable
appropriate

suitable
true
accurate
correct
precise
right

just
sound
good
decent

Synonyms
adj buoyant

soaring
light
loose
free

hollow
volatile
inflated
swimming

unattached
unsubstantial
wafting
sailing

hovering
nonsubmersible
unsinkable

Antonyms

heavy

submerged

sunk

Synonyms
adj hazy

dark
shady
ghostly
chimerical
cloudy

dim
dreamy
faint
illusory
imaginary

indistinct
obscure
unsubstantial
vague
visionary

adumbral
umbral

Antonyms

bright
light

clear
distinct

Synonyms
adj incorporeal

disembodied
immaterial
insubstantial

metaphysical
spiritual
unbodied

unsubstantial
discarnate
discorporate

nonmaterial

Synonyms
adj dreamy

abstracted
astral
calming
chimerical
daydreaming
excellent
fanciful
fantastic
gentle
idealistic

imaginary
immaterial
impractical
intangible
introspective
marvelous
misty
musing
mythical
nightmarish

otherworldly
out of this world
pensive
phantasmagoric
preoccupied
quixotic
shadowy
soothing
speculative
unreal

unsubstantial
utopian
vague
visionary
whimsical
introvertive
lulling
phantasmagorical
relaxing
woolgathering

Synonyms
adj immaterial

aerial
airy
bodiless
celestial
disembodied
dreamy
ethereal
ghostly
heavenly
impalpable

imponderable
incorporate
incorporeal
insensible
insubstantial
intangible
metaphysical
psychic
shadowy
spectral

spiritual
subjective
supernatural
unbodied
uncorporal
unearthly
unsubstantial
unworldly
apparitional
asomatous

disbodied
discarnate
dreamlike
nonmaterial
spiritlike
unembodied
unfleshly
wraithlike

Synonyms
adj imaginary

abstract
apocryphal
assumed
chimeric
chimerical
conceptual
deceptive
delusive
dreamy
fabulous
fanciful

fantastic
fantastical
fictional
hallucinatory
hypothetical
ideal
illusive
illusory
imaginative
imagined
legendary

made-up
mythological
nonexistent
phantasmal
phantasmic
quixotic
shadowy
spectral
supposed
supposititious
theoretical

trumped up
unreal
unsubstantial
visionary
whimsical
apparitional
dreamed-up
dreamlike
fancied
figmental
fool’s paradise

Synonyms
adj immaterial

aerial
airy
bodiless
celestial
disembodied
dreamy
ethereal
ghostly
heavenly
impalpable

imponderable
incorporate
incorporeal
insensible
insubstantial
intangible
metaphysical
nonphysical
psychic
shadowy

spectral
spiritual
subjective
supernatural
uncorporal
unearthly
unsubstantial
unworldly
apparitional
asomatous

disbodied
discarnate
dreamlike
nonmaterial
spiritlike
unembodied
unfleshly
wraithlike

Synonyms
adj implausible

doubtful
dubious
far out
farfetched
fishy
flimsy
impossible

improbable
inconceivable
incredible
obscure
problematic
puzzling
shaky

suspect
thin
too much
unbelievable
unconvincing
unreasonable
unsubstantial

weak
for the birds
full of holes
reachy
won’t hold water
won’t wash

Synonyms
adj immaterial

aerial
airy
bodiless
celestial
disembodied
dreamy
ethereal
ghostly
heavenly
impalpable

imponderable
incorporate
incorporeal
insensible
insubstantial
intangible
metaphysical
nonphysical
psychic
shadowy

spectral
spiritual
subjective
supernatural
unbodied
unearthly
unsubstantial
unworldly
apparitional
asomatous

disbodied
discarnate
dreamlike
nonmaterial
spiritlike
unembodied
unfleshly
wraithlike

Synonyms
adj pale

anemic
ashen
ashy
blanched
bloodless
cadaverous
colorless
deathlike
dim
dull
faded

faint
feeble
ghastly
gray
haggard
inadequate
ineffective
ineffectual
insubstantial
livid
lurid

pallid
pasty
poor
sallow
sick
sickly
spectral
thin
unsubstantial
wan
washed-out

watery
waxen
weak
white
bleached
doughy
waxlike
whitish

Synonyms
adj infirm

ailing
anemic
debilitated
decrepit
delicate
failing
faint
feeble

flimsy
fragile
frail
halting
ill
insecure
insubstantial
irresolute

lame
puny
shaky
unsound
unstable
unsubstantial
vacillating
wavering

weak
wobbly
anile
enfeebled
faltering
laid low
sensile

Synonyms
adj light

trivial
inconsequential
ethereal
agile
airy
atmospheric
buoyant
crumbly
dainty
delicate
downy
easy
effervescent

feathery
filmy
flimsy
floating
fluffy
friable
frothy
graceful
insubstantial
lightweight
lithe
little
loose

meager
nimble
petty
porous
portable
sandy
sheer
slender
slight
small
spongy
sprightly
thin

trifling
unsubstantial
featherweight
floatable
gossamery
imponderous
light as a feather
light-footed
sylphlike
tissuelike
unheavy

Antonyms

important

significant