expel vs exhaust

expel is not a noun while exhaust is a noun.

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

As verbs, expel and exhaust are synonyms defined as:

Other synonyms of expel include discharge, eject, release.

expel (noun)	exhaust (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

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