A man or woman of Boston in America: from, the number of pompkins raised and eaten by the people of that country. Pompkinshire; Boston and its dependencies.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Pompaginis * PoneyNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes