possible vs possibility

possible and possibility both are nouns.

Word	Noun	Adjective	Verb	Adverb
possible	Yes	Yes	No	No
possibility	Yes	No	No	No

As nouns, possibility is a hypernym of possible; that is, possibility is a word with a broader meaning than possible:

Other hypernyms of possible include opening, possible action.

possible (noun)	possibility (noun)
something that can be done	a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
an applicant who might be suitable	a possible alternative
	a future prospect or potential
	capability of existing or happening or being true

possible (adjective)	possibility (adjective)
capable of happening or existing
existing in possibility