Green’s Dictionary of Slang

carnie n.4

[while carnival workers have their own jargon, and this presumably refers to it, it is not rhy. sl. but is best-known for the incorporation of the infix -iz- infix (1)]

(US prison) a form of rhyming slang used by the Aryan Brotherhood.

Show quotations
D. Grann ‘The Brand’ in New Yorker 16 Feb. 168/2: [T]he Aryan Brotherhood [. . . .] developed elaborate ways to communicate. [. . .] [T]hey whispered through vents in ‘carnie,’ a convoluted rhyming code language. (‘Bottle stoppers’ meant ‘coppers.).