An Irishman; Ireland being famous for its large bogs, which furnish the chief fuel in many parts of that kingdom.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Body of Divinity bound in Black Calf * Bog TrotterNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes