give the game away

US /ɡɪv ðə ɡeɪm əˈweɪ/
UK /ɡɪv ðə ɡeɪm əˈweɪ/
"give the game away" picture
1.

entregar o jogo, revelar o segredo

to reveal a secret or surprise, often unintentionally

:
Don't give the game away by telling her about the surprise party.
Não estrague a surpresa contando a ela sobre a festa surpresa.
His nervous laughter almost gave the game away.
O riso nervoso dele quase entregou o jogo.