Definition of kryptonite in English:

kryptonite

Pronunciation /ˈkriptəˌnīt/ /ˈkrɪptəˌnaɪt/

noun

  • 1(in the fictional word of the comic book, TV, and film character Superman) an alien mineral that has the property of depriving Superman of his powers.

    ‘the evil Lex Luthor diminishes Superman's powers with kryptonite’
    1. 1.1Something that can seriously weaken or harm a particular person or thing.
      ‘flip-flopping on issues can be kryptonite to presidential candidates’
      ‘such uncertainties are kryptonite for the bond market’

Origin

1940s from Krypton, the name of Superman's home planet (kryptonite is usually depicted as a green mineral that came to earth from Krypton, following its destruction).

Pronunciation

kryptonite

/ˈkriptəˌnīt/ /ˈkrɪptəˌnaɪt/