catch off guard(redirected from off one's guard)
Also found in: Dictionary, Thesaurus.
catch (one) off guard
To engage, take advantage of, or seize upon one when one is not especially careful, vigilant, or prepared for danger or surprises. He's got a lot of tricky moves, so make sure he doesn't catch you off guard! The soldiers moved in quickly, hoping to catch the enemy troops off guard. I think I caught him off guard when I told him I was resigning.
catch someone off guardand catch one off (one's) guard
Fig. to catch a person at a time of carelessness. Tom caught Ann off guard and frightened her. She caught me off my guard, and my hesitation told her I was lying.
catch off guard
see under off guard.