English▸ noun special words or expressions that are used by a particular profession or group and are difficult for others to understand:
legal jargon.
▪ archaic a form of language regarded as barbarous, debased, or hybrid.
– ORIGIN late Middle English (originally in the sense ‘twittering, chattering’, later ‘gibberish’): from Old French jargoun, of unknown origin. The main sense dates from the mid 17th century.