colloquialism vs buddy-buddy

colloquialism is a noun but buddy-buddy is not a noun.

Word	Noun	Adjective	Verb	Adverb
colloquialism	Yes	No	No	No
buddy-buddy	No	Yes	No	No

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

colloquialism (adjective)	buddy-buddy (adjective)
	(used informally) associated on close terms