ill-usage vs cruelty

ill-usage and cruelty both are nouns.

Word	Noun	Adjective	Verb	Adverb
ill-usage	Yes	No	No	No
cruelty	Yes	No	No	No

As nouns, cruelty is a hyponym of ill-usage; that is, cruelty is a word with a more specific, narrower meaning than ill-usage:

Other hyponyms of ill-usage include child abuse, child neglect, persecution, inhuman treatment.

ill-usage (noun)	cruelty (noun)
cruel or inhumane treatment	a cruel act; a deliberate infliction of pain and suffering
	the quality of being cruel and causing tension or annoyance
	feelings of extreme heartlessness