adjective
Definition: Describing something that is perfectly vertical or straight up and down.
Example: The carpenter used a level to ensure the wall was plumb before securing it.
adverb
Definition: In a straight vertical line or directly; completely.
Example: The ball fell plumb into the hole without bouncing.
noun
Definition: A heavy weight attached to a line, used to find the vertical direction or measure water depth.
Example: The carpenter used a plumb to ensure the wall was perfectly vertical.
transitive verb
Definition: To measure the depth of something, especially water, or to examine something in detail.
Example: The engineer used a tool to plumb the depth of the river before construction.