Green’s Dictionary of Slang

(UK Und.) the picking of a lock.

1591		Greene Second Part of Conny-Catching in Grosart (1881–3) X 86: In Lifting Law. The Pickelocke is called a Charme. He that watcheth, a Stond. Their engins, Wrefters. Picking the lock, Farsing. The gaines gotten, Pelfrey.
1608		Dekker Belman of London F4: Picking of the locke is called Farsing.