A hagged old woman; a miserable, scraggy, worn-out harlot, fit to take her bawd’s degree: derived from the French word HARIDELLE, a worn-out jade of a horse or mare.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
See also the definition in Nathan Bailey's 1736 dictionary of canting and thieving slang.
Harp * HarryNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes