不备 bùbèi unprepared Origin Definitions Defs Strokes Stroke Words Sentences Sents 乘人不备 chéngrénbùbèi catch off-guard to take advantage of someone when they are unprepared or to take someone by surprise出其不意，攻其不备 chūqíbùyì, gōngqíbùbèi surprise attack To catch an enemy off guard with a surprise attack.