Lingo (6)
I believe the answer is:
'lingo' is the definition.
(I know that lingo can be written as patois)
This is all the clue.
(Other definitions for patois that I've seen before include "Local dialect heard in patios" , "Informal local dialect" , "Dialect or jargon" , "Spoken regional dialect" , "Dialect or non-standard language" .)