Sad

adjective, sadder, saddest.
1.
affected by unhappiness or grief; sorrowful or mournful:
to feel sad because a close friend has moved away.
2.
expressive of or characterized by sorrow:
sad looks; a sad song.
3.
causing sorrow:
a sad disappointment; sad news.
4.
(of color) somber, dark, or dull; drab.
5.
deplorably bad; sorry:
a sad attempt.
6.
Obsolete. firm or steadfast.
1.
seasonal affective disorder.
noun
1.
the 14th letter of the Arabic alphabet.
adjective sadder, saddest
1.
feeling sorrow; unhappy
2.
causing, suggestive, or expressive of such feelings: a sad story
3.
unfortunate; unsatisfactory; shabby; deplorable: her clothes were in a sad state
4.
(Brit, informal) ludicrously contemptible; pathetic: he’s a sad, boring little wimp
5.
(of pastry, cakes, etc) not having risen fully; heavy
6.
(of a colour) lacking brightness; dull or dark
7.
(archaic) serious; grave
verb
8.
(NZ) to express sadness or displeasure strongly
abbreviation
1.
seasonal affective disorder
noun

See seasonal affective disorder

SAD abbr.
seasonal affective disorder
sad

Systems Analysis Definition
SAD
seasonal affective disorder