Green’s Dictionary of Slang

a pickpocket, esp. one who specializes in stealing watches.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1873		Sl. Dict.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1895		Crowe Aus. Sl. Dict. 93: Watchmaker or Watchmaker in a Crowd, a pickpocket; a watch stealer.