confirm
Americanverb (used with object)
-
to establish the truth, accuracy, validity, or genuineness of; corroborate; verify.
This report confirms my suspicions.
- Synonyms:
- validate, authenticate, substantiate, prove
- Antonyms:
- disprove
-
to acknowledge with definite assurance.
Did the hotel confirm our room reservation?
-
to make valid or binding by some formal or legal act; sanction; ratify.
to confirm a treaty;
to confirm her appointment to the Supreme Court.
- Antonyms:
- invalidate
-
to make firm or more firm; add strength to; settle or establish firmly.
Their support confirmed my determination to run for mayor.
- Synonyms:
- fix
- Antonyms:
- shake
-
to strengthen (a person) in habit, resolution, opinion, etc..
The accident confirmed him in his fear of driving.
-
to administer the religious rite of confirmation to.
verb
-
(may take a clause as object) to prove to be true or valid; corroborate; verify
-
(may take a clause as object) to assert for a second or further time, so as to make more definite
he confirmed that he would appear in court
-
to strengthen or make more firm
his story confirmed my doubts
-
to make valid by a formal act or agreement; ratify
-
to administer the rite of confirmation to
Other Word Forms
Derived Forms
Etymology
Origin of confirm
First recorded in 1250–1300; from Latin confirmāre “to strengthen, confirm” ( see con-, firm 1); replacing Middle English confermen, from Old French, from Latin, as above
Explanation
When you need to make sure before you leave that you have a reservation, you often call ahead to confirm, that is, to make sure that your tickets or space are set aside for you. The firm in confirm should give you a clue as to the word's meaning: to shore up or verify something. When you make sure something is set, or firm, you confirm it. The word comes from the Latin con- "together, altogether," and firmāre "make firm," so confirm originally meant roughly "to make (something) altogether firm."
Vocabulary lists containing confirm
Jim Burke's Academic Vocabulary List
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The SAT: Language of the Test, List 3
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The Language of Standardized Tests, List 2
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Police, emergency services and the Red Cross could not confirm reports of deaths during the protests.
From Barron's • Jun. 2, 2026
Once SpaceX prices the IPO, you have to confirm your indication of interest to potentially receive an allocation.
From Barron's • Jun. 1, 2026
During that stage, teams will directly measure the aircraft's supersonic flight signature to confirm that it is producing the quiet supersonic thump it was designed to generate.
From Science Daily • Jun. 1, 2026
But Greiff's analysis so far suggests it only affects the heath-star moss, and to a limited extent one other type of moss, although more work is needed to confirm the findings.
From BBC • May 30, 2026
The soldier asked Mrs. Surratt to confirm the man’s story.
From "Chasing Lincoln's Killer" by James L. Swanson
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
