EDGE,
as, Fall Back, fall Edge; i.e. At all Adventures; used to express a villainous and daring Resolution for Mischief, whatever may be the Consequence.
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Entry taken from 1736 Canting Dictionary, by Nathan Bailey.
The Vulgar Tongue originally collected by Grose, 1811.
Also see examples in Canting Songs and Slang Rhymes collected by John S. Farmer (1896).