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

The United Nations migration agency has warned that humanitarian efforts in North Darfur may come to a complete halt unless immediate funding and safe delivery of relief supplies are ensured. —Rebecca Schneid, Time, 26 Nov. 2025

Health experts warn the number of illnesses in this outbreak could rise as officials reopen investigations into cases of infant botulism from earlier in the year. —Alexandra Banner, CNN Money, 26 Nov. 2025

Ukraine warns of Russian push near Zaporizhzhia As peace talks continue, Ukraine’s military has reported heavy fighting in the southern Zaporizhzhia region, warning that Russian forces are pressing forward near the town of Huliaipole. —Matthew Robinson, MSNBC Newsweek, 26 Nov. 2025

Yvette Marquez-Sharpnack, the 15-year author of the Mexican food blog Muy Bueno, recently warned her more than 190,000 Facebook followers. —Davey Alba, Fortune, 26 Nov. 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