GIGGER,
a Door, Dub the Gigger, that we may ravage the Ken, i. e. Open the Door with the Pick-lock, that we go in and rob the House.
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Entry taken from 1736 Canting Dictionary, by Nathan Bailey.
Gigger in the 1811 Vulgar Tongue
Also see examples in Canting Songs and Slang Rhymes collected by John S. Farmer (1896).