To pay one’s shot; to pay one’s share of a reckoning. Shot betwixt wind and water; poxed or clapped.
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.
Short-heeled Wench * Shotten HerringNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes