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

Mireles warned Grays Ferry residents near the collapse site would hear loud noises Sunday into Monday as the recovery mission continued. —Tom Ignudo, CBS News, 13 Apr. 2026

Other signs warned of danger from crumbling masonry overhead, though there was none of the scaffolding that might accompany such notices. —Rebecca Mead, New Yorker, 13 Apr. 2026

Ukrainian President Volodymyr Zelenskyy promised to abide by the ceasefire, but warned there would be a swift military response to any violations. —ABC News, 12 Apr. 2026

Haiti, the most impoverished country in the Western Hemisphere, has been hit the hardest by rising oil prices that experts warn will deepen a spiraling humanitarian crisis. —Evens Sanon, Los Angeles Times, 12 Apr. 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
• 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