fossil vs colloquialism

fossil and colloquialism both are nouns.

Word	Noun	Adjective	Verb	Adverb
fossil	Yes	Yes	No	No
colloquialism	Yes	No	No	No

fossil (noun)	colloquialism (noun)
the remains (or an impression) of a plant or animal that existed in a past geological age and that has been excavated from the soil	a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech
someone whose style is out of fashion

fossil (adjective)	colloquialism (adjective)
characteristic of a fossil