colloquialism vs irregardless

colloquialism is a noun but irregardless is not a noun.

Word	Noun	Adjective	Verb	Adverb
colloquialism	Yes	No	No	No
irregardless	No	No	No	Yes

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

colloquialism (adverb)	irregardless (adverb)
	regardless; a combination of irrespective and regardless sometimes used humorously