colloquialism vs can of worms

colloquialism and can of worms both are nouns.

Word	Noun	Adjective	Verb	Adverb
colloquialism	Yes	No	No	No
can of worms	Yes	No	No	No

colloquialism (noun)	can of worms (noun)
a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech	a source of unpredictable trouble and complexity