1.a person, a piece of clothing, a performance, etc. that is extremely attractive or impressive引人注目（或令人印象深刻）的人（或服装、演出等）◆Her daughter’s an absolute knockout. 她的女儿绝对令人倾倒。2. (in boxing拳击) a blow that is so hard that your opponent falls to the ground and cannot get up within a limited time, so losing the fight击倒对手的一击；击倒对手获胜