possible action vs possibility

possible action and possibility both are nouns.

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

As nouns, possible action and possibility are synonyms defined as:

Other synonyms of possible action include opening.

possible action (noun)	possibility (noun)
a possible alternative	a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
	a possible alternative
	a future prospect or potential
	capability of existing or happening or being true