General English

  • verb to inform someone of a possible danger
  • verb to inform someone that something is likely to happen



  • verb to say that something dangerous is about to happen or that there is a possible danger


  • verb to inform another person of a danger or threat
  • verb to inform another person that their actions or conduct are unacceptable and that they will be punished if it happens again

Origin & History of “warn”

Warn, and its German relative warnen, go back to a prehistoric west Germanic *warnōjan. this was formed from the base *war- ‘watch, be on one’s guard, take care’, which also produced English ward, ware, wary, etc. Germanic *warnjan, which evidently had close links with *warnōjan, was borrowed into French, and surfaced in English as garnish.