affirm

UK: /əˈfɜː^rm/ US: /əˈfɝm/ ,(ə fûrm′)

WordReference Random House Learner's Dictionary of American English © 2025

af•firm /əˈfɜrm/   v. [~ + object]

1. to assert positively;
   say (something) is true:
   to affirm one's loyalty.
   [~ + that clause]
   He affirmed that he would not reveal my secret.
2. to confirm or ratify, esp. of a court decision:
   The judgment was affirmed.
3. to express agreement with;
   support;
   uphold:
   I affirmed my client's claim.

af•firm•a•ble, adj. 

WordReference Random House Unabridged Dictionary of American English © 2025

af•firm  (ə fûrm′), v.t. 

1. to state or assert positively;
   maintain as true:
   to affirm one's loyalty to one's country; He affirmed that all was well.
2. to confirm or ratify:
   The appellate court affirmed the judgment of the lower court.
3. to assert solemnly:
   He affirmed his innocence.
4. to express agreement with or commitment to;
   uphold;
   support:
   to affirm human rights.

v.i. 

5. Law
   • to state something solemnly before a court or magistrate, but without oath.
   • to ratify and accept a voidable transaction.
   • (of an appellate court) to determine that the action of the lower court shall stand.

• Latin
• Middle French afermer
• Latin affirmāre, equivalent. to af- af- + firmāre to make firm (see firm¹); replacing Middle English a(f )fermen
• 1300–50

af•firm′a•ble, adj. 
af•firm′a•bly, adv. 
af•firm′er, n. 
af•firm′ing•ly, adv. 
Synonyms

• 1. aver, asseverate, depose, testify. See declare. 
• 2. approve, endorse.

Antonyms

• 1. deny.

Collins Concise English Dictionary © HarperCollins Publishers::

affirm / əˈfɜːm/ verb (mainly tr)

1. (may take a clause as object) to declare to be true; assert positively
2. to uphold, confirm, or ratify
3. (intransitive) to make an affirmation

Etymology: 14th Century: via Old French from Latin affirmāre to present (something) as firm or fixed, assert, from ad- to + firmāre to make firm¹

afˈfirmer, afˈfirmant noun