upon one's guard

1. 1.

   vigilant

   “on guard against con artists”

   “must remain on your guard in such a situation”

   Synonymson guardon one's guardon your guard

   Similarwary

Questions about upon one's guard

What does upon one's guard mean?

upon one's guard means "vigilant".

What is another word for upon one's guard?

Close synonyms include on guard, on one's guard, on your guard. Each sense on this page lists its own synonyms, because a word with several meanings rarely has one substitute that works for all of them.