warn
- 01 B1 Intermediate
to tell someone that something bad or dangerous might happen.
to inform someone in advance of an impending danger, problem, or other unpleasant situation. Transitive, often taking a direct object followed by 'of' or 'about'.
Simple“The radio announcer warned drivers about the thick fog on the motorway.”
In context“Meteorologists warned the coastal residents of the approaching storm, urging them to evacuate before the surge reached the lower streets.”
UsageCommonly used in the patterns 'warn someone of something' or 'warn someone that...'.
PitfallHe warned me to not go there. He warned me not to go there.When using 'warn' with an infinitive, the 'not' should come before 'to'.
- 02 B1 Intermediate
to tell someone not to do something because it is a bad idea.
to caution or admonish someone against a specific course of action or unacceptable behaviour.
Simple“My doctor warned me not to eat too much salt.”
In context“The legal advisor warned the board against signing the contract without a thorough review of the indemnity clauses.”
UsageOften followed by 'against' plus a gerund, or 'not to' plus an infinitive.
- 03 B2 Upper Intermediate
to tell someone they must leave a place or stay away from it.
to advise or formally order someone to depart or to remain at a distance. Often used with 'off'.
Simple“The security guard warned the teenagers off the private property.”
In context“The farmer used a loud whistle to warn the hikers off his fields during the lambing season.”
UsageFrequently appears as the phrasal verb 'warn off'.
Usage warned people · warn residents
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.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.