Bad or rank tobacco: from mondongo, a Spanish word signifying tripes, or the uncleaned entrails of a beast, full of filth.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Mumpers Hall * MungNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes