A disagreeable object. It will be an eye-sore as long as she lives, said by a man whose wife was cut for a fistula in ano.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
EyeNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes