Green’s Dictionary of Slang

a shoplifter, one who steals goods from shops while pretending to be a legitimate customer.

1661		Hue and Cry after Mercurius Democritus 8: The number of vicious Artists are unknown to the Mrs [i.e. Masters] and the Wardens of their own fencing Mobs [...] the life of which Company are High-way Pads, Glasiers, Shop-lifts, Fob-sylers [sic], instead of Bung -Tipers [sic] Bulkers,a nd some for the Mill, Budg and Snug.
1671		‘L.B.’ New Academy of Complements 204: The tenth is a Shop-lift that carries a Bob, / When he ranges the City the Shops for to rob.
1674		Head Canting Academy (2nd edn) 82: The Shop-Lift [...] is most commonly well-clad, and one that wants more of Grace than Wit.
c.1698		B.E. Dict. Canting Crew n.p.: Shop-lift c. one that Steals under pretence of Cheap’ning.