irrespective vs disregardless

irrespective and disregardless both are adverbs.

Word	Noun	Adjective	Verb	Adverb
irrespective	No	No	No	Yes
disregardless	No	No	No	Yes

As adverbs, irrespective and disregardless are synonyms defined as:

irrespective and disregardless: in spite of everything; without regard to drawbacks

Other synonyms of irrespective include disregarding, no matter, regardless.

irrespective (adverb)	disregardless (adverb)
in spite of everything; without regard to drawbacks	in spite of everything; without regard to drawbacks