trump card

英 [ˈtrʌmp kɑːd]

美 [ˈtrʌmp kɑːrd]

n. 王牌; 绝招; 杀手锏

牛津词典

noun

王牌；绝招；杀手锏
something that gives you an advantage over other people, especially when they do not know what it is and you are able to use it to surprise them

noun

a playing card in the suit that has been declared trumps
1. the ace of trumps is a sure winner
Synonym:trump

Not many people know it but shutting up can be the trump card in a lot of situations.
不是每个人都知晓这一点，但沉默在很多场合下的确是最好的王牌。
Henry is the trump card of France.
亨利是法国队中的皇牌。
But China also has a trump card that others don't:$ 3.2 trillion in cash reserves, by far the biggest hoard in the world.
但中国手里握有一张别国不具有的“王牌”：3.2万亿美元的外汇储备，这是全球规模最大的外储。
This is my trump card. I never use it easily.
这可是我的杀手锏，不轻易使用的！
The United States also needs to help people adjust to change, so that it can maintain its greatest trump card: openness to trade, investment, people, and ideas.
美国还需要帮助民众适应变化，以便确保它的最大优势：对贸易、投资、民众和观念的开放。
Jack showed his trump card at the last minute.
杰克在最后一刻打出了王牌。
His other trump card is his financial independence.
韩寒的另外一张王牌就是他的经济独立性。
I'll play my trump card in the final round.
在最后一局我会出王牌。
But the real disappointment for Yahoo shareholders is that the company threw away its trump card so cheaply.
但真正令雅虎股东失望的是，雅虎如此轻易地丢掉了自己的王牌。
Nor can we any longer fall back on our historical trump card of geographic isolation.
我们也不再能依靠天然屏障的历史王牌。