patois vs drop-dead

patois is a noun but drop-dead is not a noun.

Word	Noun	Adjective	Verb	Adverb
patois	Yes	No	No	No
drop-dead	No	No	No	Yes

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

patois (adverb)	drop-dead (adverb)
	stunningly or breathtakingly