proper name · An imperial sword granted by the emperor to a high official, conferring the power to act with delegated authority and perform summary executions.

钦差大臣手持尚方剑，有权先斩后奏。

proper name · A metaphorical mandate or supreme authority, especially in fiction, allowing one to act with impunity or absolute power.

这份文件就是他的尚方剑，让他可以放手改革。