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 kingdom sounded sirens multiple times on Wednesday across several southern Saudi cities, warning residents to take shelter for fear of potential attacks. — Arkansas Online, 10 Sep. 2026

In an exclusive interview with CNBC, UBS CEO Sergio Ermotti has warned against investor complacency as geopolitical and economic risks rise. — Leonie Kidd, CNBC, 10 Sep. 2026

The labor law, which had expired July 1, would have required companies to significantly increase goat herder pay, which businesses and their advocates in the agriculture industry warned could lead to companies shutting down or pivoting to sheep. — Lizzie Kane, Sacbee.com, 9 Sep. 2026

Iran’s Revolutionary Guard warns crews near Kuwait and Bahrain to abandon tankers as both sides maneuver to control the Strait of Hormuz, a vital chokepoint for global oil shipments. — Konstantin Toropin, Los Angeles Times, 9 Sep. 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