patois vs argot

patois and argot both are nouns.

Word	Noun	Adjective	Verb	Adverb
patois	Yes	No	No	No
argot	Yes	No	No	No

As nouns, patois and argot are synonyms defined as:

patois and argot: a characteristic language of a particular group (as among thieves)

Other synonyms of patois include cant, jargon, lingo, slang, vernacular.

patois (noun)	argot (noun)
a regional dialect of a language (especially French); usually considered substandard	a characteristic language of a particular group (as among thieves)
a characteristic language of a particular group (as among thieves)