withal vs notwithstanding

withal and notwithstanding both are adverbs.

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

As adverbs, withal and notwithstanding are synonyms defined as:

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

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

withal (adverb)	notwithstanding (adverb)
together with this	despite anything to the contrary (usually preceding a concession)
despite anything to the contrary (usually preceding a concession)