Green’s Dictionary of Slang

1. (Und.) one who breaks the shop window and extracts the booty during a smash-and-grab raid.

1865		Shields Dly Gaz. 6 Nov. 2/4: A ‘smasher’ is a man able to [...] ‘star a glaze,’ that is smash a jeweller’s window and remove the goods.
1872		E. Crapsey Nether Side of NY 22: As the hog-thieves went down, the ‘smashers’ came up [...] Their first point is to provide a plate of iron about nine inches square, with a handle upon one side, and armed with this to smash in the shop-windows of jewellers [...] and steal the valuables behind the glass.
1881		Newcastle Courant 2 Dec. 6/6: Bill the Smasher soon ‘got his pecker up’.
1925		N. Lucas Autobiog. of a Thief 83: ‘Nebby’ himself was the actual ‘smasher’ and to see him smash a pane of glass with a brick, insert his gloved hand through the hole, and extract a ‘dummy’ tray (to scale) [...] was an education.
1935		Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks 10: Smasher: A jeweller’s shop window.

2. (UK und.) a housebreaker, a safe-cracker.

1882		A. Trumble Crooked Life in Nat. Police Gaz. 13 May 3/2: The ‘smasher’ is one who pries open the shutters of the first house he comes across with a jimmy or small crow .
1906		D. Stewart Vultures of the City in Illus. Police News 8 Dec. 12/3: ‘I’m the champion cracksman Bill Lowery, alias Bulldog the Smasher’.