SNEAK,
He goes upon the Sneak at Darkmans, He privately gets into Houses or Shops at Night and Steals undiscovered.
· 
· 
Entry taken from 1736 Canting Dictionary, by Nathan Bailey.
Sneak in the 1811 Vulgar Tongue
Also see examples in Canting Songs and Slang Rhymes collected by John S. Farmer (1896).