unadaptability vs unfitness

unadaptability and unfitness both are nouns.

Word	Noun	Adjective	Verb	Adverb
unadaptability	Yes	No	No	No
unfitness	Yes	No	No	No

As nouns, unfitness is a hypernym of unadaptability; that is, unfitness is a word with a broader meaning than unadaptability:

unadaptability: the inability to change or be changed to fit changed circumstances
unfitness: lacking the power to perform

Other hypernyms of unadaptability include inability.

unadaptability (noun)	unfitness (noun)
the inability to change or be changed to fit changed circumstances	the quality of not being suitable
	lacking the power to perform
	poor physical condition; being out of shape or out of condition (as from a life of ease and luxury)