abuse vs ill-treat

abuse is a noun but ill-treat is not a noun.

Word	Noun	Adjective	Verb	Adverb
abuse	Yes	No	Yes	No
ill-treat	No	No	Yes	No

As verbs, abuse and ill-treat are synonyms defined as:

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

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

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