A blackguard, a rascal, a term of reproach. Mill the bloody bugger; beat the damned rascal.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Buggy * Bulk and FileNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes