Green’s Dictionary of Slang

the world and practice of pickpocketing; also attrib.; thus dipping-bloke, a pickpocket; dipping gag, pickpocketing.

c.1864		A. Stephens ‘The Chickaleary Cove’ 🎵 Off to Paris I shall go, to show a thing or two / To the dipping blokes what hangs about the caffes.
1868		H.L. Williams Black-Eyed Beauty 36: ’Taint you Edwards, for the pocket-dipping on the Third Avenue car?
1894		‘The Rocks Push Eisteddfod’ Bird o’ Freedom (Sydney) in J. Murray Larrikins (1973) 87: Just to raise a quid or two to find the ‘lush’ and ‘prog’, / A few strolled out with ‘flimsies,’ or went ‘dipping’.
1900		A.H. Lewis ‘Crime That Failed’ Sandburrs 78: It spoils me hooks for dippin’.
a.1909		press cutting in J. Ware Passing Eng. of the Victorian Era 109/2: Mr Selfe: What is meant by ‘dipping’? The policeman: It’s the last new word – it means picking pockets.
1914		J. McCree ‘Types’ Variety Stage Eng. Plays 🌐 When you’re out to do some dipping, / Leather stripping, pocket nipping.
1914		Truth (Melbourne) 14 Feb. 5/6: Ed is alleged to be one of the ‘dipping’ brigade [...] He was charged with attempted larceny from the person.
1928		J. Callahan Man’s Grim Justice 36: She eventually persuaded me to cut the dipping gag (quit picking pockets).
1928		M.C. Sharpe Chicago May (1929) 25: There were women who ran dipping-houses in Custom House Place. They were like booths, into which you took your man. If you succeeded in getting him in, the landlady soon helped you trim him.
1938		G. Kersh Night and the City 102: ‘Stealing?’ ‘Dipping; lifting money out of a mug’s pocket.
1946		S. Jackson Indiscreet Guide to Soho 118: ‘Dipping’ is not merely a matter of bumping against you.
1971		D. Goines Dopefiend (1991) 28: We don’t have no dippin’ in this house.
1974		G.F. Newman You Flash Bastard 157: Those Paks copped for the lot, must’ve cleared up every reported case of dipping we’ve had.
1987		P. Robinson Gallows View (2002) 52: The first time it had been fun, a change from dipping, or mugging the odd tourist.
2003		(con. 1932) W. Woodruff Beyond Nab End 29: The old man and two of his older sons had done time for what Ben called ‘dippin’ or ‘shoot-flyin’.