harshness vs cruelty

harshness and cruelty both are nouns.

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

As nouns, harshness and cruelty are synonyms defined as:

harshness and cruelty: the quality of being cruel and causing tension or annoyance

Other synonyms of harshness include cruelness.

harshness (noun)	cruelty (noun)
the quality of being harsh or rough or grating to the senses	a cruel act; a deliberate infliction of pain and suffering
excessive sternness	the quality of being cruel and causing tension or annoyance
the roughness of a substance that causes abrasions	feelings of extreme heartlessness
the quality of being cruel and causing tension or annoyance