Thin, meagre-faced. Weasel-gutted; thin-bodied; a weasel is a thin long slender animal with a sharp face.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Wear A—e * WeddingNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes