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

Wildlife officials have warned of the dangers of wolves becoming overly accustomed to feeding on cattle as opposed to their natural prey of elk or deer. — Clara Harter, Los Angeles Times, 9 July 2026

Oman’s Foreign Ministry also condemned the latest attacks against Bahrain and Kuwait in an X post, warning that the escalation of military tensions in the region poses a threat to not only its security, but overall maritime safety. — Jamie Gray, NBC news, 9 July 2026

The guards warned their response would expand to other American bases in the region if the US retaliates. — Nadeen Ebrahim, CNN Money, 9 July 2026

And on July 1, two SSPX bishops consecrated the four new bishops in a highly visible ceremony in Écône, Switzerland, after being warned that doing so would result in their excommunication. — Judy L. Thomas, Kansas City Star, 9 July 2026

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
• morne
• mourn
• porn
• scorn
• shorn
• sworn
• thorn

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