Vulgar abusive language, such as was spoken by ribalds. Ribalds were originally mercenary soldiers who travelled about, serving any master far pay, but afterwards degenerated into a mere banditti.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Rib * RibbinNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes