catch (someone) napping

Translations
застать (кого-то) врасплох
The sudden storm caught the hikers napping.
Внезапная буря застала туристов врасплох.
Definitions
To surprise someone who is not paying attention or is unprepared, often resulting in them being caught off guard or at a disadvantage.
Words
catch

verb
застать
someone

pronoun
кого-то
napping

verb
дремлющим