child abuse vs maltreatment

child abuse and maltreatment both are nouns.

Word	Noun	Adjective	Verb	Adverb
child abuse	Yes	No	No	No
maltreatment	Yes	No	No	No

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

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

child abuse (noun)	maltreatment (noun)
the physical or emotional or sexual mistreatment of children	cruel or inhumane treatment