in stories and films, a fictional (= invented) substance that can hurt the character Superman, who is extremely strong and not hurt by most things

something that hurts or damages a person or thing that usually seems strong

A slowing economy is kryptonite for the U.S. dollar. 经济放缓可能对美元造成致命打击。

His personal kryptonite comes in the form of a romantic entanglement. 陷入桃色纠葛是他的个人弱点。