keep one's eyes open vs colloquialism

keep one's eyes open is not a noun while colloquialism is a noun.

Word	Noun	Adjective	Verb	Adverb
keep one's eyes open	No	No	Yes	No
colloquialism	Yes	No	No	No

keep one's eyes open (noun)	colloquialism (noun)
	a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech

keep one's eyes open (verb)	colloquialism (verb)
pay attention; be watchful