Green’s Dictionary of Slang

(UK Und.) an operator of a rigged game of ‘chance', e.g. the three-card trick or thimble-rig n. (1)

1842

Morn. Post (London) 29 June 7/5: The [...] are known to the police as fellows called ‘nabblers,’ who visit faits and horse races, and are adept at the ‘thimble rig’ and other games.