A phrase used by thieves when the officers or turnkeys are examining their countenance. As the traps are taking our likeness; the officers are attentively observing us.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
lightning * liliputianNathan Bailey's 1721 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes