An opening, or means of escape. To find a loophole in an act of parliament; i.e. a method of evading it,
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Loonslate * Lop-sidedNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes