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

Poland also sounded the alarm about Russia, with Polish Prime Minister Donald Tusk warning on Thursday that Moscow could send drones or missiles into NATO countries allied with Ukraine in the coming months. — David Zimmermann, The Washington Examiner, 19 Sep. 2026

Donald Tusk, Poland's prime minister, warned on Thursday before departing for Ukraine that Moscow is planning hybrid strikes with drones or rockets on European countries supporting Kyiv, among them Poland. — Arkansas Online, 19 Sep. 2026

According to the Red Note post, a local social worker warned Huang before the trip that any border crossing could trigger a review of her family’s eligibility for welfare. — Sylvie Zhuang, CNN Money, 18 Sep. 2026

McNeely painted this suite of panels just after that 1982 spinal injury left her in a wheelchair, when her doctors warned her that making large paintings would be a challenge. — Emily Watlington, ARTnews.com, 18 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