disregardless vs regardless

disregardless is not an adjective while regardless is an adjective.

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

As adverbs, disregardless and regardless are synonyms defined as:

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

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

disregardless (adjective)	regardless (adjective)
	(usually followed by `of') without due thought or consideration

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