unfamiliar vs familiar

unfamiliar is not a noun while familiar is a noun.

Word	Noun	Adjective	Verb	Adverb
unfamiliar	No	Yes	No	No
familiar	Yes	Yes	No	No

unfamiliar (noun)	familiar (noun)
	a spirit (usually in animal form) that acts as an assistant to a witch or wizard
	a person attached to the household of a high official (as a pope or bishop) who renders service in return for support
	a friend who is frequently in the company of another

unfamiliar (adjective)	familiar (adjective)
not known or well known	well known or easily recognized
	within normal everyday experience; common and ordinary; not strange
	having mutual interests or affections; of established friendship
	(usually followed by `with') well informed about or knowing thoroughly