Money in the pocket: the swell is well breeched, let’s draw him; the gentleman has plenty of money in his pocket, let us rob him.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Breast Fleet * BreechesNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes