WordNet sense 1 (informal language consisting of words and expressions that are not considered appropriate for formal occasions; often vituperative or vulgar):

slang expression, slang term

WordNet sense 2 (a characteristic language of a particular group (as among thieves)):

argot, cant, jargon, lingo, patois, vernacular, jargon

WordNet sense 3 (fool or hoax):

cod, dupe, fool, gull, befool, put on, take in, put one across, put one over