Meaning of “guard” - Learner’s Dictionary

guard

verb [ T ] uk us /ɡɑːd/
PROTECT

B2 to protect someone or something from being attacked or stolen:

Soldiers guarded the main doors of the embassy.
PREVENT ESCAPE

B2 to watch someone and make certain that they do not escape from a place:

Five prison officers guarded the prisoners.

(Definition of “guard verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)