gambler, n. — Green’s Dictionary of Slang

gambler n.

[Johnson, Dictionary (1755), cites it as ‘a cant word, I suppose, for...gamester’ and defines it as ‘a knave whose practice it is to invite the unwary to game and cheat them’. The cheating inference had worn off by early 19C; even so, the modern professional gambler is assumed to depend on skill, albeit honest, rather than on luck]

1. a confidence trickster who drops a supposedly valuable object, e.g. a ring, a wallet, and rather than claim it for himself, persuades a passer-by to buy it from him.

1735		Proceedings Old Bailey 2 July 88/1: The Prisoner has been a Gambler [...] for several Years past. [...] [note] A Gambler is one of the Modern Cant Names for a Money Dropper.
1737		Bailey Universal Etym. Eng. Dict. n.p.: gambler, a guinea-dropper; one class of sharpers.
1738		Proc. Old Bailey 11 Oct. 149/2: I heard nothing of him 'till he was taken as a Gambler, (or Money Dropper) the Tuesday following [...] He being taken on Tuesday for Gambling, he sent Mr. Bushel, an Apothecary in St. Paul's Church-yard, to the Compter with me.

2. a cheating card- or dice-player.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.

SE in slang uses

In compounds

gambler’s roll (n.)

see under roll n.