lag vs imprison

lag is a noun but imprison is not a noun.

Word	Noun	Adjective	Verb	Adverb
lag	Yes	No	Yes	No
imprison	No	No	Yes	No

As verbs, lag and imprison are synonyms defined as:

Other synonyms of lag include gaol, immure, incarcerate, jail, jug, put away, put behind bars, remand.

lag (noun)	imprison (noun)
the act of slowing down or falling behind
one of several thin slats of wood forming the sides of a barrel or bucket
the time between one event, process, or period and another

lag (verb)	imprison (verb)
throw or pitch at a mark, as with coins	lock up or confine, in or as in a jail
cover with lagging to prevent heat loss	confine as if in a prison
hang (back) or fall (behind) in movement, progress, development, etc.
lock up or confine, in or as in a jail