A jockey term for a horse that throws about his fore legs irregularly: the idea is taken from a kettle drummer, who in beating makes many flourishes with his drumsticks.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
To Drub * DrunkNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes