A counterfeit signature. A forgery. Tell the macers to mind their fakements; desire the swindlers to be careful not to forge another person’s signature.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Fair * FallallsNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes