warn

verb

ˈwȯrn 

warned; warning; warns

transitive verb

1

a

: to give notice to beforehand especially of danger or evil

b

: to give admonishing advice to : counsel

c

: to call to one's attention : inform

2

: to order to go or stay away

—often used with off

intransitive verb

: to give a warning

warner noun

Synonyms of warn

• alert
• advise

Examples of warn in a Sentence

I had been warned about the difficulties of the job.

She warned me that the stove was still hot.

“This won't be easy,” he warned.

Nobody warned me about the dangers.

I warned him to be careful, but he didn't listen to me.

She warned us not to go too close to the fire.

Recent Examples on the Web

Patients are being warned to stop using some glucose monitors made by Abbott Diabetes Care after the company found malfunctioning sensors may be linked to hundreds of adverse events and several deaths, the Food and Drug Administration said Tuesday. —Kerry Breen, CBS News, 3 Dec. 2025

Traffic officials warned drivers to avoid a major downtown road on Wednesday afternoon. —Sally Krutzig, Idaho Statesman, 3 Dec. 2025

Back-to-back clipper systems are expected to bring lake-effect snow to Michigan's eastern Upper Peninsula this week, prompting a winter storm warning. —Sarah Moore, Freep.com, 3 Dec. 2025

But Democratic elections officials and voting rights advocates warn that the requests go far beyond what is necessary for routine federal reviews, and may expose millions of voters' personal information to misuse. —MSNBC Newsweek, 3 Dec. 2025

Word History

Etymology

Middle English warnen, going back to Old English wearnian, warnian "to be on one's guard, make aware, put on one's guard," going back to West Germanic *warnōjan- (whence Middle Dutch waernen "to provide with, give notice of a danger," Old High German warnōn), probably causative derivative of Germanic *wara- "cognizant, watchful" — more at ware entry 1

First Known Use

before the 12th century, in the meaning defined at transitive sense 1a

Phrases Containing warn

• I have to warn you
• pre-warn
• warn off

Rhymes for warn

• borne
• bourn
• bourne
• corn
• morn
• mourn
• porn
• scorn
• shorn
• sworn
• thorn
• torn

Kids Definition

warn

verb

ˈwȯ(ə)rn 

1

a

: to give notice to beforehand especially of danger or evil

b

: to give advice to : counsel

2

: to order to go or stay away

warned us off their land

warner noun