call someone's bluff
US /kɔl ˈsʌm.wʌnz blʌf/
UK /kɔl ˈsʌm.wʌnz blʌf/

1.
iemands bluf callen, iemand uitdagen
to challenge someone to prove that what they are saying is true, or to show that they are not afraid to do something that they have threatened to do
:
•
She threatened to quit, but I decided to call her bluff and see if she would actually do it.
Ze dreigde op te stappen, maar ik besloot haar bluf te callen en te kijken of ze het echt zou doen.
•
The politician made a bold claim, and the journalists decided to call his bluff by demanding evidence.
De politicus deed een gewaagde bewering, en de journalisten besloten zijn bluf te callen door om bewijs te vragen.