able vs ability

able is not a noun while ability is a noun.

Word	Noun	Adjective	Verb	Adverb
able	No	Yes	No	No
ability	Yes	No	No	No

able (noun)	ability (noun)
	the quality of being able to perform; a quality that permits or facilitates achievement or accomplishment
	possession of the qualities (especially mental qualities) required to do something or get something done

able (adjective)	ability (adjective)
(usually followed by `to') having the necessary means or skill or know-how or authority to do something
having inherent physical or mental ability or capacity
have the skills and qualifications to do things well
having a strong healthy body