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
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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
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confirmabilitynoun
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confirmernoun
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unconfirmabilitynoun
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preconfirmverb (used with object)
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reconfirmverb (used with object)
-
unconfirmverb (used with object)
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confirmableadjective
-
confirmatoryadjective
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nonconfirmingadjective
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confirminglyadverb
Inflected Forms
Participles
Conjugated Forms
Present
-
confirmsimple
-
confirmssimple
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have confirmedperfect
-
has confirmedperfect
-
am confirmingprogressive
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are confirmingprogressive
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is confirmingprogressive
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have been confirmingperfect progressive
-
has been confirmingperfect progressive
Past
-
confirmedsimple
-
had confirmedperfect
-
was confirmingprogressive
-
were confirmingprogressive
-
had been confirmingperfect progressive
Future
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.
NASA's rovers have already detected organic molecules in Martian rocks, but those compounds alone cannot confirm that life was once present.
From Science Daily • Jul. 9, 2026
“We remain confident that, when the facts are evaluated fairly and thoroughly, the NBA will confirm exactly what we have said from the beginning: We have not done what we are accused of doing.”
From Los Angeles Times • Jul. 9, 2026
We can’t predict how Congress will vote on Blanche’s confirmation next week, but it’s worth noting that every Republican in the Senate voted to confirm him as deputy attorney general last year.
From Slate • Jul. 9, 2026
Booking.com said property owners must confirm they have the right to list their property, and would "take the necessary action if they are found not to be operating in compliance with local laws".
From BBC • Jul. 8, 2026
“Since we cannot confirm that this is merely food, we will confiscate this package.”
From "Finding Junie Kim" by Ellen Oh
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.
