- 出其不意 chūqíbùyì to take someone by surpriseto act when the other party is least expecting it (idiom); to catch someone off guard
- 事出不意 shìchūbùyì unexpected turn of eventshappening or occurring unexpectedly; an event that comes as a surprise
- 出其不意，攻其不备 chūqíbùyìgōngqíbùbèi to catch an enemy off guardTo catch an enemy off guard with a surprise attack; an idiom from Sunzi's "The Art of War" [[孙子兵法|孫子兵法|sun1 zi3 bing1 fa3]]
- 辞不意逮 cíbùyìdài unable to express oneselfwords fail to convey the intended meaning; poorly expressed
