exhaust vs expel

exhaust is a noun but expel is not a noun.

Word	Noun	Adjective	Verb	Adverb
exhaust	Yes	No	Yes	No
expel	No	No	Yes	No

As verbs, exhaust and expel are synonyms defined as:

Other synonyms of exhaust include discharge, eject, release.

exhaust (noun)	expel (noun)
system consisting of the parts of an engine through which burned gases or steam are discharged
gases ejected from an engine as waste products

exhaust (verb)	expel (verb)
wear out completely	eliminate (a substance)
eliminate (a substance)	cause to flee
use up the whole supply of	force to leave or move out
use up (resources or materials)	remove from a position or office
deplete