Green’s Dictionary of Slang

1. (US) to spoil.

c.1800

‘The Progress of Sir Jack Brag’ in E.A. Dolph Sound Off! 503: As to Sa-ra-tog’ he came, thinking how to jo the game.

2. (US) to be exhausted.

1932

J.L. Kuethe ‘Johns Hopkins Jargon’ in AS VII:5 333: Joed—tired; exhausted.

3. (US gambling) to rig a game.

1988		M. Gryczan Carnival Secrets 203: Joing—rigging a game so it cannot be won [HDAS].
2012		W. Keyser ‘Carny Lingo’ in http://goodmagic.com 🌐 Joing — To ‘jo’ a game is to rig it so that it cannot be won.