cruelty vs maltreatment

cruelty and maltreatment both are nouns.

Word	Noun	Adjective	Verb	Adverb
cruelty	Yes	No	No	No
maltreatment	Yes	No	No	No

As nouns, maltreatment is a hypernym of cruelty; that is, maltreatment is a word with a broader meaning than cruelty:

Other hypernyms of cruelty include abuse, ill-treatment, ill-usage.

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