mistreat vs abuse

mistreat is not a noun while abuse is a noun.

Word	Noun	Adjective	Verb	Adverb
mistreat	No	No	Yes	No
abuse	Yes	No	Yes	No

As verbs, mistreat and abuse are synonyms defined as:

Other synonyms of mistreat include ill-treat, ill-use, maltreat, step.

mistreat (noun)	abuse (noun)
	improper or excessive use
	cruel or inhumane treatment
	a rude expression intended to offend or hurt

mistreat (verb)	abuse (verb)
treat badly	change the inherent purpose or function of something
	use wrongly or improperly or excessively
	use foul or abusive language towards
	treat badly