warn

The story

1. Proto-Indo-European · inherited from*wer-“to be aware; give heed”
2. Proto-Germanic · inherited from*warnōną“to warn; take heed”
3. Old English · inherited fromwarnian“to take heed; warn”
4. Middle English · inherited fromwarnen
5. English todaywarn

From Middle English warnen, warnien (“to warn; admonish”), from Old English warnian (“to take heed; warn”), from Proto-Germanic *warnōną (“to warn; take heed”), from Proto-Indo-European *wer- (“to be aware; give heed”). Cognate with Dutch waarnen (obsolete), German Low German warnen, German warnen, Swedish varna, Icelandic varna.

Words from the same roots

First known use, by meaning

• from 11th c. To make (someone) aware of impending danger, evil, etc.
• from at least the 13th c. To notify or inform (someone, about something).
• from 11th c. To caution or admonish (someone) against unwise or unacceptable behaviour.