unforgivingness vs toughness

unforgivingness and toughness both are nouns.

Word	Noun	Adjective	Verb	Adverb
unforgivingness	Yes	No	No	No
toughness	Yes	No	No	No

As nouns, toughness is a hypernym of unforgivingness; that is, toughness is a word with a broader meaning than unforgivingness:

Other hypernyms of unforgivingness include formidability.

unforgivingness (noun)	toughness (noun)
The quality of having no allowance for weakness.	the property of being big and strong
	enduring strength and energy
	impressive difficulty
	the elasticity and hardness of a metal object; its ability to absorb considerable energy before cracking