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.Tom RussoIn his career Thome has hit less than .240 against lefties. Lefthanded power pitching is Thome's Kryptonite …—Joe Posnanski
Joe PosnanskiIronic people always dissolve when confronted with earnestness, it's their kryptonite.—Gillian Flynn
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
Lorie ParchEffortlessly good-looking, he was also a talented writer—that combo was my kryptonite.—Taylor Orci
Taylor OrciExamples of kryptonite in a Sentence
Recent Examples on the Web
The Oilers have proven to be the kryptonite to even the most Superman-ish of Kings teams, with Edmonton the place the Kings postseasons go to die.
—Kevin Baxter, Los Angeles Times, 3 May 2025
Matt LaFleur’s kryptonite since becoming Green Bay’s head coach in 2019 has been the San Francisco 49ers.
—Rob Reischel, Forbes, 20 Nov. 2024
While Palace are a stylistic kryptonite, the league table is the most reliable gauge in measuring a team’s ability and Villa sit five places higher than Saturday’s opponents, with 12 more points.
—Jacob Tanswell, New York Times, 27 Apr. 2025
The Superman roller coaster that was once the tallest and fastest in the world has been exposed to a lethal dose of kryptonite and will never fly again at Six Flags Magic Mountain.
—Brady MacDonald, Oc Register, 29 Mar. 2025
See All Example Sentences for kryptonite
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Kevin Baxter, Los Angeles Times, 3 May 2025
Matt LaFleur’s kryptonite since becoming Green Bay’s head coach in 2019 has been the San Francisco 49ers.
—Rob Reischel, Forbes, 20 Nov. 2024
While Palace are a stylistic kryptonite, the league table is the most reliable gauge in measuring a team’s ability and Villa sit five places higher than Saturday’s opponents, with 12 more points.
—Jacob Tanswell, New York Times, 27 Apr. 2025
The Superman roller coaster that was once the tallest and fastest in the world has been exposed to a lethal dose of kryptonite and will never fly again at Six Flags Magic Mountain.
—Brady MacDonald, Oc Register, 29 Mar. 2025
See All Example Sentences for kryptonite
Cite this Entry
“Kryptonite.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/kryptonite. Accessed 21 May. 2025.
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