kryptonite n.

in the fictional world of the comic book hero Superman: a substance that renders Superman weak when he is exposed to it; (hence, in figurative or allusive use) something that can weaken or damage a particular person or thing; an Achilles heel

Typically depicted as a green mineral that originated on Superman’s home planet Krypton, and fell to Earth as a meteorite. Other types have appeared in various stories, having different properties.

[< Krypton, name of Superman’s home planet, + -ite, suffix used to form names of minerals]


  • 1943 The Meteor from Krypton in Adventures of Superman (transcript of radio programme) in (OED Archive) page image

    I watched Dr. Whistler put that meteor through 101 tests... Finally he told me what that meteor is... The name of that meteor is kryptonite.

  • 1945 Newsweek 15 Oct. 28/3

    Radio’s Superman soon will be defeated for the first time by an atomic man, a German injected with kryptonite.

  • 1949 Superman Returns to Krypton! 12 in Superman (#61) Nov. page image

    Those meteorites…. They're particles of Krypton, flung into space!... That compound gives off rays which apparently can only affect Kryptonites…. And that’s why it weakens me.… I couldn’t carry that deadly kryptonite without fainting!

  • 1951 Exit—Superman in Action Comics (#161) Oct. 11 page image

    That ship was lined with kryptonite…once inside, I was weak as a baby!

  • 1964 Boston Globe 19 Jan. 2

    The compulsory branding of every cigarette pack with a danger warning was proposed Saturday by the Federal Trade Commission…. The rules would prohibit, for example, any advertisement saying: ‘Buy Brand X, the cigarette that gives you extra protection’ or ‘Brand Y contains the new improved kryptonite filter.’

  • 1966 R. Fariña Been Down So Long It Looks Like Up To Me 34

    Superman winging over Metropolis, cape fluttering in the wild wind. Safe as long as no one pulls any Kryptonite ouf ot a lead box.

  • 1967 East Village Other 1 Aug. 5/3

    South America will be the poetic kryptonite for Superman USA.

  • 1991 Jimmy Olsen’s Blues (song, perf. ‘Spin Doctors’)

    Lois Lane please put me in your planner / Yeah, Lois Lane you don’t need no Superman / Come on downtown and stay with me tonight / I got a pocket full of kryptonite.

  • 1992 Antigonish Review Spring 118

    Girls of her sort are kryptonite to the developing hearts and souls of adolescent boys.

  • 2002 New Yorker 20 May 60/2

    Shaq is dealing with injuries that he never thought he’d have to deal with. Even Superman had his kryptonite, but after ten years there are only so many hits of kryptonite you can take.

  • 2015 M. Miller 500 Dates 157

    Yes, communication—or, as we men refer to it, Kryptonite.

Research requirements

antedating 1943

Earliest cite

Superman radio broadcast

Last modified 2021-07-20 15:40:44
In the compilation of some entries, HDSF has drawn extensively on corresponding entries in OED.