A coward: a cockpit phrase, all but game cocks being styled dunghills. To die dunghill; to repent, or shew any signs of contrition at the gallows. Moving dunghill; a dirty, filthy man or woman. Dung, an abbreviation of dunghill, also means a journeyman taylor who submits to the law for regulating journeymen taylors’ wages, therefore deemed by the flints a coward. See Flints.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Dunegan * DunnockNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes