cruelness vs brutality

cruelness and brutality both are nouns.

Word	Noun	Adjective	Verb	Adverb
cruelness	Yes	No	No	No
brutality	Yes	No	No	No

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

Other hyponyms of cruelness include ferociousness, savagery, viciousness, murderousness.

cruelness (noun)	brutality (noun)
the quality of being cruel and causing tension or annoyance	a brutal barbarous savage act
	the trait of extreme cruelty