high-flown vs colloquialism

high-flown is not a noun while colloquialism is a noun.

Word	Noun	Adjective	Verb	Adverb
high-flown	No	Yes	No	No
colloquialism	Yes	No	No	No

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

high-flown (adjective)	colloquialism (adjective)
of high moral or intellectual value; elevated in nature or style
pretentious (especially with regard to language or ideals)