colleague vs collegial

colleague is a noun but collegial is not a noun.

Word	Noun	Adjective	Verb	Adverb
colleague	Yes	No	No	No
collegial	No	Yes	No	No

colleague (noun)	collegial (noun)
an associate that one works with
a person who is member of one's class or profession

colleague (adjective)	collegial (adjective)
	characterized by or having authority vested equally among colleagues
	of or resembling or typical of a college or college students