kryptonite

From a fictional radioactive element, kryptonite, that has a detrimental effect on the otherwise invulnerable character Superman. Apparently formed as krypton (“a chemical element, Kr”) +‎ -ite.

• IPA^(key): /ˈkɹɪptənaɪt/

• Audio (Southern England):

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kryptonite (usually uncountable, plural kryptonites)

1. (figuratively) The one weakness of something or someone that is otherwise invulnerable.

   Synonyms: Achilles heel, weakness; see also Thesaurus:weak spot

   • 1991 October 25, Bryan Miller, “Restaurants: John Clancy's”, in New York Times‎:

     The terrific seven-grain bread here is the kryptonite of restaurant reviewers: two mini-loaves and you are incapacitated.

   • 2006 March 25, Jonathan Leggett, “Cult musicians”, in The Guardian:

     So while recording or sampling a Charlie Manson track makes for shock rock kudos aplenty, a devotion to Hubbard is kryptonite for credibility.

   • 2016, Marlon Orlando Cole, Orphans: Nature's Beloved, page 93:

     We all have our own kryptonite or kryptonites, so don't tempt yourself by listening to so-called friends who are just demonic tools being used to bring you under.

   • 2025 May 24, “OnlyFans has a shot at ditching its NSFW image”, in FT Weekend, Lex., page 20:

     But of course porn is kryptonite to many investors.

2. (slang) Crack cocaine.

kryptonite (third-person singular simple present kryptonites, present participle kryptoniting, simple past and past participle kryptonited)

1. To expose to, or attack with, kryptonite.
   • 1998, Phillip Gwynne, Deadly Unna?, Melbourne: Penguin, page 173:

     And even those two were pretty puny, like Superman after he had been kryptonited.

2. (figuratively) To destroy, wreck, or ruin; to affect adversely, as Superman is affected by kryptonite.

• kryptonite on Wikipedia.Wikipedia