Acquainted with, knowing the business. Stow the books, the culls are awake; hide the cards, the fellows know what we intended to do.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Autem Quaver TubNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes