n [ C ] ( AmE )
1. ( also thimblerig [ U ]) a game in which one person tries to trick the other players. The first person places a small object under one of three upside-down cups, nut shells, etc. He or she then quickly moves the cups around, and the others try to guess which contains the object, sometimes betting on their choice.
2. any action that is intended to cheat or deceive somebody:
She promised to double my money, but it was just a shell game.