A weak silly fellow easily imposed on. To pigeon; to cheat. To milk the pigeon; to attempt impossibilities, to be put to shifts for want of money. To fly a blue pigeon; to steal lead off a church.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Pig Running * PigeonsNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes