knockout
/ˈnɒkaʊt/noun
1- an act of knocking someone out, especially in boxing（尤指拳击中）击倒对手取胜：
as modifier a knockout blow.击倒对手取胜的一拳。
1.1
- Brit. a tournament in which the loser in each round is eliminated〈英〉淘汰赛。
1.2
- in sing. informal an extremely attractive or impressive person or thing〈非正式〉异常动人的人（或物）, 给人留下深刻印象的人（或物）：
he must have been a knockout when he was young.
他年轻的时候一定非常吸引人。