Green’s Dictionary of Slang

copper v.1

[cop v.; + ? faro jargon copper a bet, to bet that a given card will lose]
(US)

1. to steal, to embezzle.

[US]T. Hamilton Men and Manners II 387: One member of Congress [...] was charged with selling franks at twopence apiece, and thus coppering his pocket at the expense of the public [DA].
[US](US newspaper ) Aug. n.p.: He’s been in office for a long while an’ never coppered a d——n cent [DA].

2. to kill.

[US]A.H. Lewis Wolfville 55: Still Enright’s all-wise enough to copper the Greaser.

3. to outwit, to spoil.

[US]J.H. Beadle Western Wilds 46: He staked a pile of ‘chips’ and won; then made and lost, and made and lost alternately, selling his stock when ‘broke,’ [...] till the tail of his last mule was ‘coppered on the jack’.
[US]‘Mark Twain’ Life on the Mississippi (1914) 268: The safe way [...] is to copper the operation, and at the same time buy enough property in Vicksburg to square you up in case they win.
[US]A.H. Lewis Wolfville 99: The victim [...] don’t copper the play by makin’ vain remarks, but brings his gatlin’ into play surprisin’. [Ibid.] 330: Of course, I’m heap interested in this yere snake knowledge [...] But it sorter coppers my appetite.
[UK]R. Beach Pardners (1912) 57: I’d sure copper this move and play her to lose.
[US]Van Loan ‘The Good Old Wagon’ Lucky Seventh (2004) 206: Your wrist was cut, but I’ve got that bet coppered.
[US]P.A. Rollins Cowboy 80: Faro’s terms permitted one puncher to ‘keep cases’ on another man [...] and further permitted this puncher, if dissatisfied with these actions or plans, to ‘copper’ them by initiating a diametrically opposite sort of performance or scheme.
[US]M. Harris ‘Facing the Mob’ in Gangland Stories Feb. [Internet] You’ll have a sweet time explaining to the other gangs how come you wasn’t bumped off when Bad News coppered your bet.
[US]Z. Grey Robbers’ Roost 218: Wal, you coppered it with the ace.

4. to obtain, to make sure of getting.

[US]Galaxy (N.Y.) July 57: ‘Who’s payin’? I’m dead broke?’ ‘What! Cleaned out?’ ‘You bet. But if that dealer hadn’t railroaded, I’d a got square copperin’ the ace.’.
[UK]A. Day Mysterious Beggar 264: If you’re a bit skeery, then ’till the thing’s well coppered, you can nark ’round on the sly.
[US]W. Irwin Love Sonnets of a Hoodlum XX n.p.: All the chronic glad hand-claspers came To copper invites for the wedding day.
[US]J. Lait ‘Canada Kid’ Beef, Iron and Wine (1917) 151: A lotta judges is tryin’ to copper the lowdown on the bad boy problem.
[US]C. Coe Hooch! 49: He won’t waste any time gettin’ to Swinnerton an’ that’s the little bet I’ll copper!
[US]R. Chandler ‘Guns At Cyrano’s’ Red Wind (1946) 237: He tried to copper his bet on your blackmail racket.
[US]Sugarfoot [film script] In this game you can’t copper no bets [W&F].
[US](con. mid–late 19C) S. Longstreet Wilder Shore 34: Coppering your bet (a six-sided black chip on top) is a no bet.