notwithstanding vs however

notwithstanding and however both are adverbs.

Word	Noun	Adjective	Verb	Adverb
notwithstanding	No	No	No	Yes
however	No	No	No	Yes

As adverbs, notwithstanding and however are synonyms defined as:

notwithstanding and however: despite anything to the contrary (usually preceding a concession)

Other synonyms of notwithstanding include all the same, at the same time, even so, nevertheless, nonetheless, still, withal, yet.

notwithstanding (adverb)	however (adverb)
despite anything to the contrary (usually preceding a concession)	despite anything to the contrary (usually preceding a concession)
	in whatever way or manner
	to whatever degree or extent
	by contrast; on the other hand