To go into a tradesman’s shop under the pretence of purchasing rings or other light articles, and while examining them to shift some up the sleeve of the coat. Also to ask for change for a guinea, and when the silver is received, to change some of the good shillings for bad ones; then suddenly pretending to recollect that you had sufficient silver to pay the bill, ask for the guinea again, and return the change, by which means several bad shillings are passed.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Pinch * To Pinch On the Parson’s SideNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes