eat up vs exhaust

eat up is not a noun while exhaust is a noun.

Word	Noun	Adjective	Verb	Adverb
eat up	No	No	Yes	No
exhaust	Yes	No	Yes	No

As verbs, eat up and exhaust are synonyms defined as:

Other synonyms of eat up include consume, deplete, eat, expend, run through, use, use up, wipe out.

As verbs, exhaust is a hyponym of eat up; that is, exhaust is a word with a more specific, narrower meaning than eat up:

eat up (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

eat up (verb)	exhaust (verb)
finish eating all the food on one's plate or on the table	wear out completely
use up (resources or materials)	eliminate (a substance)
enclose or envelop completely, as if by swallowing	use up the whole supply of
	use up (resources or materials)
	deplete