obviously vs colloquialism

obviously is not a noun while colloquialism is a noun.

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

obviously (noun)	colloquialism (noun)
	a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech

obviously (adverb)	colloquialism (adverb)
unmistakably (`plain' is often used informally for `plainly')