One who deserves and has narrowly escaped the gallows, a slip-gibbet, one for whom the gallows is said to groan.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Scandal Proof * ScapegraceNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes