Thin-visaged: from their cheeksbeing almost transparent. Or else, lenten jawed; i.e. having the jaws of one emaciated by a too rigid observation of Lent. Dark lanthorn; a servant or agent at court, who receives a bribe for his principal or master.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Lansprisado * LapNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes