kryptonite

American  

[krip-tuh-nahyt] / ˈkrɪp təˌnaɪt /

noun

1. Usually Kryptonite a fictional radioactive substance that is the only thing capable of hurting or weakening the otherwise invulnerable superhero Superman.

   Exposure to Kryptonite nullifies Superman's powers and immobilizes him with pain.

2. Sometimes Kryptonite something that a person or thing cannot defend against or defeat; a nemesis or bête noire.

   The team has not found a way to stop the triple option attack, which has been their kryptonite over the last several years.

   Garlic oil is kryptonite for aphids.

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Etymology

Origin of kryptonite

Coined in 1943 by writer and producer George Lowther (1913–1975); krypton ( def. ) + -ite ¹ ( def. )

Example Sentences

Flores’s persistence has puzzled even some of his industry peers, who say that California’s regulatory regime is kryptonite for oil-and-gas firms.

From The Wall Street Journal

And unfortunately for Kipchoge, hills happen to be his personal kryptonite.

From The Wall Street Journal

Regardless, the book is Hedda’s kryptonite: Her lifestyle—the only reason she got married to begin with—has been built on the presumption that George will get the university job.

From The Wall Street Journal

But for all their dominance, there was never any doubt about the Dodgers’ kryptonite.

From The Wall Street Journal

For Ohtani’s hitting, pitching has been his kryptonite this season.

From Los Angeles Times