cruelty vs atrocity

cruelty and atrocity both are nouns.

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

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

Other hyponyms of cruelty include impalement, inhumanity.

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