What does warn mean?
Warn means to alert someone to a danger, problem, or possible negative consequence, usually so that they can take precautions. The verb commonly takes a person as its object, with the information supplied through a phrase such as 'warn someone about a risk,' 'warn someone of a danger,' or 'warn someone against doing something.' It can also introduce a statement of fact: 'I warned her that the meeting had been cancelled.' The word is used in both formal and informal contexts and can range from practical safety notices to serious cautions about risks. Its power lies in the combination of information and concern: to warn is not merely to notify, but to put someone on guard or discourage an action that may lead to harm. Related forms include warning, as in a warning sign, and warned, the past tense and past participle.
verbTo tell someone about a possible danger, problem, or undesirable consequence so that they can take precautions. It can also mean to caution someone against a particular action or behaviour.
- To alert someone to a possible danger, problem, or consequence.
- To caution someone against doing something.
- To give advance notice or warning about a situation.
"The guide warned us not to cross the river after heavy rain."
"Meteorologists warned that the storm could bring flooding to coastal areas."
"She warned us not to open the package until we had read the instructions."
Warn originally meant to be on guard or take care, so its modern sense developed from the idea of alerting someone to something they might otherwise overlook.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does warn come from?
Warn descends from Old English w(e)arnian, associated with taking heed or guarding oneself, and ultimately with a Germanic root meaning to be wary or on guard. The modern sense developed from the idea of alerting someone to a risk. Wary is a close relative, and warrant and warranty belong to a related branch of the same Germanic word family; modern German warnen preserves a closely related form.
How warn is actually used
Warn is usually transitive: warn someone about or of something, or warn someone against doing something. In less formal contexts, it is often followed by an object clause, as in 'I warned him that the road was closed.'
Easily confused with warn
To warn someone is to alert them to a danger or caution them, whereas worn means badly used, damaged, or in the past participle of wear.