nevertheless vs nonetheless

nevertheless and nonetheless both are adverbs.

Word	Noun	Adjective	Verb	Adverb
nevertheless	No	No	No	Yes
nonetheless	No	No	No	Yes

As adverbs, nevertheless and nonetheless are synonyms defined as:

nevertheless and nonetheless: despite anything to the contrary (usually preceding a concession)

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

nevertheless (adverb)	nonetheless (adverb)
despite anything to the contrary (usually preceding a concession)	despite anything to the contrary (usually preceding a concession)