facultative vs faculty

facultative is not a noun while faculty is a noun.

Word	Noun	Adjective	Verb	Adverb
facultative	No	Yes	No	No
faculty	Yes	No	No	No

facultative (noun)	faculty (noun)
	one of the inherent cognitive or perceptual powers of the mind
	the body of teachers and administrators at a school

facultative (adjective)	faculty (adjective)
able to exist under more than one set of conditions
of or relating to the mental faculties
granting a privilege or permission or power to do or not do something
optional