colloquialism vs like mad

colloquialism is a noun but like mad is not a noun.

Word	Noun	Adjective	Verb	Adverb
colloquialism	Yes	No	No	No
like mad	No	No	No	Yes

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

colloquialism (adverb)	like mad (adverb)
	(informal) with great speed or effort or intensity; used for emphasis