Green’s Dictionary of Slang

1. to double-cross, to betray (a confidence).

1812

Vaux Vocab. of the Flash Lang. in McLachlan (1964) 229: bridge: to bridge a person, or throw him over the bridge, is, in a general sense, to deceive him by betraying the confidence he has reposed in you, and instead of serving him faithfully, to involve him in ruin or disgrace; or, three men being concerned alike in any transaction, two of them will form a collusion to bridge the third, and engross to themselves all the advantage which may eventually accrue. Two persons having been engaged in a long and doubtful contest or rivalship, he, who by superior art or perseverance gains the point, is said to have thrown his opponent over the bridge. Among gamblers, it means deceiving the person who had back’d you, by wilfully losing the game; the money so lost by him being shared between yourself and your confederates who had laid against you. In playing three-handed games, two of the party will play into each other’s hands, so that the third must inevitably be thrown over the bridge, commonly called, two poll one.

2. in gambling, to deceive one’s backer by deliberately losing the game.

1811

Lex. Balatronicum.

3. (Aus.) to display.

1923		Smith’s Wkly (Sydney) 11 Aug. 15/4: The ugma shouted fer the mob and bridges a roll thick enough to choke Big Mouth Annie.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 19: Bridge Display something.