Drink, or any brisk or windy liquor. In North America, a mixture of spruce beer, rum, and sugar, was so called. The 17th regiment had a society called the Swizzle Club, at Ticonderoga, A. D. 1760.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Swivel-eyed * Sword RacketNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes