SNUG,
All's snug; All's quiet, used by Villains, when every thing is silent and they hear no body stir to oppose their intended Rogueries.
All's snug; All's quiet, used by Villains, when every thing is silent and they hear no body stir to oppose their intended Rogueries.
Entry taken from 1736 Canting Dictionary, by Nathan Bailey.
Snug in the 1811 Vulgar Tongue
Also see examples in Canting Songs and Slang Rhymes collected by John S. Farmer (1896).