misuse vs eat up

misuse is a noun but eat up is not a noun.

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

As verbs, eat up is a hypernym of misuse; that is, eat up is a word with a broader meaning than misuse:

Other hypernyms of misuse include consume, deplete, eat, exhaust, expend, run through, use, use up, wipe out.

misuse (noun)	eat up (noun)
improper or excessive use

misuse (verb)	eat up (verb)
change the inherent purpose or function of something	finish eating all the food on one's plate or on the table
apply to a wrong thing or person; apply badly or incorrectly	use up (resources or materials)
	enclose or envelop completely, as if by swallowing