catch someone napping
US /kætʃ ˈsʌm.wʌn ˈnæp.ɪŋ/
UK /kætʃ ˈsʌm.wʌn ˈnæp.ɪŋ/

1.
pegar alguém desprevenido, surpreender alguém
to surprise someone when they are not prepared for something, especially when they are not paying attention or are doing something they shouldn't be doing
:
•
The teacher caught him napping when he was playing games on his phone during class.
O professor o pegou desprevenido quando ele estava jogando no celular durante a aula.
•
The sudden inspection caught many employees napping, as they were not following company protocols.
A inspeção repentina pegou muitos funcionários desprevenidos, pois eles não estavam seguindo os protocolos da empresa.