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

1.
застать кого-либо врасплох, поймать кого-либо на горячем
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.
Учитель застал его врасплох, когда он играл в игры на телефоне во время урока.
•
The sudden inspection caught many employees napping, as they were not following company protocols.
Внезапная проверка застала многих сотрудников врасплох, так как они не соблюдали протоколы компании.