capable vs capableness

capable is not a noun while capableness is a noun.

Word	Noun	Adjective	Verb	Adverb
capable	No	Yes	No	No
capableness	Yes	No	No	No

capable (noun)	capableness (noun)
	the quality of being capable -- physically or intellectually or legally
	an aptitude that may be developed

capable (adjective)	capableness (adjective)
(usually followed by `of') having capacity or ability
(followed by `of') having the temperament or inclination for
having the requisite qualities for
have the skills and qualifications to do things well
possibly accepting or permitting