atrocity vs cruelty

atrocity and cruelty both are nouns.

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

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

Other hypernyms of atrocity include inhuman treatment.

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