colloquialism vs picayune

colloquialism is a noun but picayune is not a noun.

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

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

colloquialism (adjective)	picayune (adjective)
	(informal) small and of little importance