Green’s Dictionary of Slang

trickery, cheating, usu. with cards.

1592

Greene Defence of Conny-Catching 37: Let mee vse it for an excuse of our Card Conny-catching: for when wee meet a country Farmer with a ful purse, a miserable miser [...] we hold it a deuotion to make him a Conny, in that he is a Caterpillar to others.