colloquialism vs topnotch

colloquialism is a noun but topnotch is not a noun.

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

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

colloquialism (adjective)	topnotch (adjective)
	of the highest quality