Bedeutung von “guard” im Essential American English Dictionary

guard

noun us /ɡɑrd/

B1 someone whose job is to protect a person or make sure that a person does not escape:

prison guards
be on your guard

to be ready to do something if a problem happens:

Companies were warned to be on their guard for suspicious packages.

(Definition von “guard noun” aus dem Webster's Essential Mini Dictionary © Cambridge University Press)