Word
warn
US/ˈwɔɹn/
UK/wˈɔːn/
Definitions
01to alert to danger
B1 · Intermediate
v. to tell someone that something bad or dangerous might happen.
v. 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'.
“The radio announcer warned drivers about the thick fog on the motorway.”
“Meteorologists warned the coastal residents of the approaching storm, urging them to evacuate before the surge reached the lower streets.”
Usage
Commonly used in the patterns 'warn someone of something' or 'warn someone that...'.
Pitfall
He 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'.
02to advise against an action
B1 · Intermediate
v. to tell someone not to do something because it is a bad idea.
v. to caution or admonish someone against a specific course of action or unacceptable behaviour.
“My doctor warned me not to eat too much salt.”
“The legal advisor warned the board against signing the contract without a thorough review of the indemnity clauses.”
Usage
Often followed by 'against' plus a gerund, or 'not to' plus an infinitive.
03to order away
B2 · Upper Intermediate
v. to tell someone they must leave a place or stay away from it.
v. to advise or formally order someone to depart or to remain at a distance. Often used with 'off'.
“The security guard warned the teenagers off the private property.”
“The farmer used a loud whistle to warn the hikers off his fields during the lambing season.”
Usage
Frequently appears as the phrasal verb 'warn off'.
Collocations
Common phrases and expressions where native English speakers use the word “warn” in context.
Verb
01. warned him not to go
“His friends warned him not to go into the dark forest alone.”
verb + noun + infinitive
02. warned the children about the danger
“The teacher warned the children about the danger of playing near the river.”
verb + noun + prep + noun
03. warned the public that
“The police warned the public that the roads were very icy.”
verb + noun + that-clause
Adverb
04. repeatedly warn the residents
“The government repeatedly warned the residents to leave before the storm arrived.”
adv + verb + noun
05. sternly warn the students
“The principal sternly warned the students about the consequences of cheating.”
adv + verb + noun
Etymology
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.
Word family
VERB
NOUN
Grammar
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.B1 PreliminaryIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.4.0–5.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 3.0–3.544–71TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.550–784
- Frequency
- Common
- Level
- B1 · IntermediateOxford
- Updated
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