poor white trash vs patois

poor white trash and patois both are nouns.

Word	Noun	Adjective	Verb	Adverb
poor white trash	Yes	No	No	No
patois	Yes	No	No	No

poor white trash (noun)	patois (noun)
(slang) an offensive term for White people who are impoverished	a regional dialect of a language (especially French); usually considered substandard
	a characteristic language of a particular group (as among thieves)