An oaken sapling, or cudgel: from a wood of that name famous for its oaks. Irish.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Shifting Ballast * Shilly-shallyNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes