A Dutch pug; a kind of lap-dog, formerly much in vogue; also a general name for a monkey.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Puffing * Pug CarpenteterNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes