certainly vs colloquialism

certainly is not a noun while colloquialism is a noun.

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

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

certainly (adverb)	colloquialism (adverb)
definitely or positively (`sure' is sometimes used informally for `surely')