on one's guard


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Related to on one's guard: warship

on (one's) guard

Especially careful or vigilant; prepared for danger or surprises. He's got a lot of tricky moves, so be on your guard! Those trails can be a bit treacherous to climb; I just hope she's on her guard.
See also: guard, on

on one's guard

see under off guard.
See also: guard, on