- a small mass of lead or other heavy material, as that suspended by a line and used to measure the depth of water or to ascertain a vertical line.Compare plumb line.
- true according to a plumb line perpendicular.
- Informal. downright or absolute.
- in a perpendicular or vertical direction.
- exactly, precisely, or directly.
- Informal. completely or absolutely: She was plumb mad. You're plumb right.
- to test or adjust by a plumb line.
- to make vertical.
- Shipbuilding. horn(def 32).
- to sound with or as with a plumb line.
- to measure (depth) by sounding.
- to examine closely in order to discover or understand: to plumb someone's thoughts.
- to seal with lead.
- to weight with lead.
- to provide (a house, building, apartment, etc.) with plumbing.
- to work as a plumber.
- out of/off plumb, not corresponding to the perpendicular; out of true.
Origin of plumb
SynonymsSee more synonyms on Thesaurus.com
- a weight, usually of lead, suspended at the end of a line and used to determine water depth or verticality
- the perpendicular position of a freely suspended plumb line (esp in the phrases out of plumb, off plumb)
- (prenominal) informal, mainly US (intensifier)a plumb nuisance
- in a vertical or perpendicular line
- informal, mainly US (intensifier)plumb stupid
- informal exactly; precisely (also in the phrase plumb on)
- (tr often foll by up) to test the alignment of or adjust to the vertical with a plumb line
- (tr) to undergo or experience (the worst extremes of misery, sadness, etc)to plumb the depths of despair
- (tr) to understand or master (something obscure)to plumb a mystery
- to connect or join (a device such as a tap) to a water pipe or drainage system
Word Origin and History for unplumb
"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.
"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.