no matter vs disregardless

no matter and disregardless both are adverbs.

Word	Noun	Adjective	Verb	Adverb
no matter	No	No	No	Yes
disregardless	No	No	No	Yes

As adverbs, no matter and disregardless are synonyms defined as:

no matter and disregardless: in spite of everything; without regard to drawbacks

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

no matter (adverb)	disregardless (adverb)
in spite of everything; without regard to drawbacks	in spite of everything; without regard to drawbacks