give the game away
US /ɡɪv ðə ɡeɪm əˈweɪ/
UK /ɡɪv ðə ɡeɪm əˈweɪ/

1.
rovinare la sorpresa, svelare il segreto
to reveal a secret or surprise, often unintentionally
:
•
Don't give the game away by telling her about the surprise party.
Non rovinare la sorpresa dicendole della festa a sorpresa.
•
His nervous laughter almost gave the game away.
La sua risata nervosa ha quasi rovinato la sorpresa.