fitness vs habitability

fitness and habitability both are nouns.

Word	Noun	Adjective	Verb	Adverb
fitness	Yes	No	No	No
habitability	Yes	No	No	No

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

Other hyponyms of fitness include making, qualification, habitableness.

fitness (noun)	habitability (noun)
the quality of being suitable	suitability for living in or on
the quality of being qualified
good physical condition; being in shape or in condition