Jh plumb

[pluhm] /plʌm/

noun
1.
J(ohn) H(arold) 1911–2001, British historian.
/plʌm/
noun
1.
a weight, usually of lead, suspended at the end of a line and used to determine water depth or verticality
2.
the perpendicular position of a freely suspended plumb line (esp in the phrases out of plumb, off plumb)
adjective
3.
(prenominal) (informal, mainly US) (intensifier): a plumb nuisance
adverb
4.
in a vertical or perpendicular line
5.
(informal, mainly US) (intensifier): plumb stupid
6.
(informal) exactly; precisely (also in the phrase plumb on)
verb
7.
(transitive) often foll by up. to test the alignment of or adjust to the vertical with a plumb line
8.
(transitive) to undergo or experience (the worst extremes of misery, sadness, etc): to plumb the depths of despair
9.
(transitive) to understand or master (something obscure): to plumb a mystery
10.
to connect or join (a device such as a tap) to a water pipe or drainage system
n.

“lead hung on a string to show the vertical line,” early 14c., from Old French *plombe, plomee “sounding lead,” and directly from Late Latin *plumba, originally plural of Latin plumbum “lead (the metal), lead ball; pipe; pencil,” a word of unknown origin, related to Greek molybdos “lead” (dialectal bolimos) and perhaps from an extinct Mediterranean language, perhaps Iberian.
v.

early 15c., “to sink” (like lead), from plumb (n.). Meaning “take soundings with a plumb” is first recorded 1560s; figurative sense of “to get to the bottom of” is from 1590s. Related: Plumbed; plumbing.
adj.

“perpendicular, vertical,” mid-15c., from plumb (n.). The notion of “exact measurement” led to extended sense of “completely, downright” (1748), sometimes spelled plump, plum, or plunk.

adverb

Completely; entirely; stone: What he said was plumb silly

[1748+; fr notions of exact extent and precision associated with the plumb bob or sailor’s plumb line (for measuring depth of water), ultimately fr Latin plumbum, ”lead”]