confirm

UK: /kənˈfɜː^rm/ US: /kənˈfɝm/ ,(kən fûrm′)

WordReference Random House Learner's Dictionary of American English © 2026

con•firm /kənˈfɜrm/   v. [~ + object]

1. to establish the truth of (something); verify:
   The secretary would not confirm the reports.
   [~ + that clause]
   confirmed that my client was there at the time of the murder.
2. to acknowledge with assurance;
   make certain:
   The hotel promised to confirm my reservation.
3. to make valid by formal or legal act;
   ratify:
   In the end she was confirmed by the Senate and appointed to the court.
4. Religion to administer the rite of confirmation to:
   He was confirmed when he was thirteen.

con•firm•a•ble, adj. 
con•firm•a•bil•i•ty /kənˌfɜrməˈbɪlɪti/  n. [uncountable]
con•firm•er, n. [countable]

WordReference Random House Unabridged Dictionary of American English © 2026

con•firm  (kən fûrm′), v.t. 

1. to establish the truth, accuracy, validity, or genuineness of; corroborate;
   verify:
   This report confirms my suspicions.
2. to acknowledge with definite assurance:
   Did the hotel confirm our room reservation?
3. 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.
4. to make firm or more firm;
   add strength to;
   settle or establish firmly:
   Their support confirmed my determination to run for mayor.
5. to strengthen (a person) in habit, resolution, opinion, etc.:
   The accident confirmed him in his fear of driving.
6. to administer the religious rite of confirmation to.

• Latin, as above
• Old French
• Latin confirmāre to strengthen, confirm (see con-, firm¹); replacing Middle English confermen
• 1250–1300

con•firm′a•ble, adj. 
con•firm′a•bil′i•ty, n. 
con•firm′er;
 
Law, con•fir•mor  (kon′fər môr′, kən fûr′mər), n.  con•firm′ing•ly, adv. 
Synonyms

• 1. prove, substantiate, authenticate, validate.
• 4. fix.

Antonyms

• 1. disprove.
• 3. invalidate.
• 4. shake.

Collins Concise English Dictionary © HarperCollins Publishers::

confirm / kənˈfɜːm/ verb (transitive)

1. (may take a clause as object) to prove to be true or valid; corroborate; verify
2. (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
3. to strengthen or make more firm: his story confirmed my doubts
4. to make valid by a formal act or agreement; ratify
5. to administer the rite of confirmation to

Etymology: 13th Century: from Old French confermer, from Latin confirmāre, from firmus firm¹

conˈfirmatory, conˈfirmative adjective