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

Lawmakers also have warned major banks, port authorities and fuel distributors that facilitating the imports could expose companies to civil or criminal liability and future congressional investigations. — David McHugh, Arkansas Online, 6 Nov. 2026

However, the conversation has also attracted a wave of caution from health professionals, warning against drawing medical conclusions from skin-deep assumptions. — Amy Francombe, Vogue, 6 Nov. 2026

Ireland’s public broadcaster RTÉ evacuated its offices after receiving an email warning that an explosive device would detonate within 45 minutes. — Aamir Khollam, Interesting Engineering, 6 Nov. 2026

Voters overwhelmingly elected candidates who are critical of data-center development — one of many potential pitfalls Anthropic warned about in its IPO prospectus last month. — Allison Morrow, CNN Money, 6 Nov. 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