plumb

1 syllable

Quick answer

As an adjective, plumb means truly vertical, as indicated by a plumb line. As an adverb, it means in a vertical direction.

Meanings of plumb

24 meanings

Truly vertical, as indicated by a plumb line.
cricketDescribing an LBW where the batsman is hit on the pads directly in front of their wicket and should be given out.

In a vertical direction; perpendicularly.
informalSquarely, directly; deeply, completely.
“It hit him plumb in the middle of his face.”
“Years ago the well plumb dried out, not a drop of water in there since.”
Completely; used as intensifiers
“clean forgot the appointment”
“I'm plumb (or plum) tuckered out”
Similar: clean, plum
Conforming to the direction of a plumb line
“The carpenter used a level to ensure the wall was perfectly plumb.”
Exactly
“fell plumb in the middle of the puddle”
Similar: plum

A little mass of lead, or the like, attached to a line, and used by builders, etc., to indicate a vertical direction.
nauticalA weight on the end of a long line, used by sailors to determine the depth of water.
The perpendicular direction or position.
The metal bob of a plumb line
Similar: plumb bob, plummet

Obsolete form of plum ("the fruit").

To determine the depth, generally of a liquid; to sound.
To attach to a water supply and drain.
figurativeTo think about or explore in depth, to get to the bottom of, especially to plumb the depths of.
To use a plumb bob as a measuring or aligning tool.
To accurately align vertically or horizontally.
To work as a plumber.
nauticalTo position vertically above or below.
Measure the depth of something
Examine thoroughly and in great depth
Adjust with a plumb line so as to make vertical

Older and rare meanings (3)

datedTo seal something with lead.
rareTo fall or sink like a plummet.
UScolloquialfigurativelyobsoleteTo trace a road or track; to follow it to its end.

Meanings from Wiktionary (CC BY-SA 4.0) and Open English WordNet (CC BY 4.0).