coup de grace

基本解释

The coup de grace is Cantor’s proof that some infinite sets are bigger than this.
這個論題是康托的殺手鐧，他用它來証明某些無限集要比這個無限集大。
Adding a new twist to the tale, the latestresearch shows that the fungal coup de grace usually occurs at solar noon, whenthe sun is at its strongest.
這個故事又增加了一個新的進展，最新的研究表明真菌的致命一擊發生在正午，即陽光最強烈的時刻。
When he had completed theexcision, and had taken his souvenir, he administered the coup de grace: asingle deep slash across the neck, from left to right.
他完成切除，拿走紀唸品之後，實施了最後的致命一擊：整個頸部從左曏右，深深的一刀。

And then he hears the coup de grace, it's the shots, one after another, and then he sees a priest staggering out, overwhelmed by it all, and then he moves onto something else.
接下來他就聽見了那致命的聲響,槍聲,一聲接著一聲,之後他看見驚魂未定的牧師踉蹌而出,然後他就調轉筆鋒寫其它事情去了
耶魯公開課 - 1871年後的法國課程節選

In the end, it will probably be Mr Aso's mediocre performance that administers the coup de grace.
ECONOMIST: The ruling LDP plays a sloppy endgame

A coup de grace is an action or event which finally destroys something, for example, an institution, which has been gradually growing weaker.