incapacity vs inability

incapacity and inability both are nouns.

Word	Noun	Adjective	Verb	Adverb
incapacity	Yes	No	No	No
inability	Yes	No	No	No

As nouns, inability is a hypernym of incapacity; that is, inability is a word with a broader meaning than incapacity:

incapacity (noun)	inability (noun)
lack of physical or natural qualifications	lacking the power to perform
lack of intellectual power	lack of ability (especially mental ability) to do something