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

Scheer warns that a lack of trust significantly erodes loyalty, innovation, and retention, impacting revenue and growth. — Rodger Dean Duncan, Forbes.com, 30 July 2026

Sacramento County is warning EBT cardholders to be wary of ongoing scams on social media targeting recipients of CalFresh and CalWORKs benefits. — Vince Basada july 29, Sacbee.com, 29 July 2026

Senate Majority Leader John Thune (R-SD) used a Wednesday lunch with White House officials to warn about the difficulty of getting elements of the SAVE America Act passed through a party-line budget process. — David Sivak, The Washington Examiner, 29 July 2026

Hikers in an area of the San Bernardino National Forest are being warned of falling rocks after one woman was injured, and another woman died after she was suspected to have been hit in the head by a large boulder. — Paris Barraza, USA Today, 29 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