“杀手锏”，中文俗语，原意指搏斗时出其不意地用锏投杀敌人的绝招，现指出其不意击敌制胜的招数，比喻看家本领。与英文俗语“trump card”意思相近，表示“an advantage that makes you more likely to succeed than other people, especially something that other people do not know about”。

例句：

看到爸爸没有如自己的意， 那孩子便使出杀手锏，哇的一声哭了起来。

When his father refused to let him have his own way, the child played his trump card by crying.

安西娅正打算亮出杀手锏，没有她的签名，就无法放款。

Anthea was about to play her trump card - without her signature none of the money could be released.