kryptonite

noun

kryp·​to·​nite ˈkrip-tə-ˌnīt 

variants or Kryptonite

in stories

: a substance that causes the comic-book character Superman to become weak when he is exposed to it

Note: In Superman stories, kryptonite in its most familiar form is a green mineral that originated as part of Superman's home planet of Krypton and that falls to Earth as a meteorite.

Superman tended to get more bummed out by Kryptonite than by anything going on in Clark Kent's life …

—Tom Russo

—often used to describe something likened to kryptonite in causing someone's weakness, failure, etc.

In his career Thome has hit less than .240 against lefties. Lefthanded power pitching is Thome's Kryptonite …

—Joe Posnanski

Ironic people always dissolve when confronted with earnestness, it's their kryptonite.

—Gillian Flynn

"Thin people know they need to either limit exposure to certain foods that trigger appetite or limit the quantity or frequency of those foods," says Gullo, whose personal kryptonite is pizza.

—Lorie Parch

Effortlessly good-looking, he was also a talented writer—that combo was my kryptonite.

—Taylor Orci

Examples of kryptonite in a Sentence

Recent Examples on the Web

But how to figure out which ones will actually play to your superpowers - and which will just be your kryptonite??? —Jeremy Schifeling, Forbes, 19 Oct. 2024

Entertainment & Arts Column: With a single word — ‘weird’ — Democrats may have found Republicans’ kryptonite July 30, 2024 Harris did nothing more, or less, than allow Trump to be Trump, un-sane-washed, while offering a very clear alternative. —Mary McNamara, Los Angeles Times, 12 Sep. 2024

Minnesota Governor Tim Walz was subpoenaed by the House Education Committee on Wednesday as part of the GOP lawmakers' latest investigation into the Democratic presidential ticket, probing into an issue that has long been Walz's kryptonite: child nutrition programs. —Sam Woodward, USA TODAY, 5 Sep. 2024

However, with great power comes limitations and Red Hulk's kryptonite is literally overheating from absorbing too much radiation. —Meredith G. White, The Arizona Republic, 12 July 2024

Word History

Etymology

Krypton, Superman's home planet + -ite entry 1

First Known Use

1943, in the meaning defined above