Definition of plumb:
- A little mass or weight of lead, or the like, attached to a line, and used by builders, etc., to indicate a vertical direction; a plummet; a plumb bob. See line, below.
- In a plumb direction; perpendicularly.
- Perpendicular; vertical; conforming the direction of a line attached to a plumb; as, the wall is plumb.
- To adjust by a plumb line; to cause to be perpendicular; as, to plumb a building or a wall.
- To seal with lead; as, to plumb a drainpipe.
- To sound with a plumb or plummet, as the depth of water; hence, to examine by test; to ascertain the depth, quality, dimension, etc.; to sound; to fathom; to test.
- To supply, as a building, with a system of plumbing.
clean, fairly, horizontal, plum, vertical, plumb bob, upright, plummet, perpendicular, fair, upright.
straight (part of speech: adjective)
straighten (part of speech: verb)