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Synonyms

certify

American  
[sur-tuh-fahy] / ˈsɜr təˌfaɪ /

verb (used with object)

certified, certifying
  1. to attest as certain; give reliable information of; confirm.

    He certified the truth of his claim.

    Synonyms:
    guarantee, validate, verify, corroborate
  2. to testify to or vouch for in writing.

    The medical examiner will certify his findings to the court.

  3. to guarantee; endorse reliably.

    to certify a document with an official seal.

  4. to guarantee (a check) by writing on its face that the account against which it is drawn has sufficient funds to pay it.

  5. to award a certificate to (a person) attesting to the completion of a course of study or the passing of a qualifying examination.

  6. to declare legally insane and committable to a mental institution.

  7. Archaic. to assure or inform with certainty.


verb (used without object)

certified, certifying
  1. to give assurance; testify; vouch for the validity of something (usually followed byto ).

certify British  
/ ˈsɜːtɪˌfaɪ /

verb

  1. to confirm or attest (to), usually in writing

    the letter certified her age

  2. (tr) to endorse or guarantee (that certain required standards have been met)

  3. to give reliable information or assurances

    he certified that it was Walter's handwriting

  4. (tr) to declare legally insane

  5. (tr) (of a bank) to state in writing on (a cheque) that payment is guaranteed

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • certifier noun
  • precertify verb (used with object)
  • recertify verb (used with object)
  • uncertifying adjective

Etymology

Origin of certify

1300–50; Middle English certifien < Middle French certifier < Late Latin certificāre, equivalent to Latin certi- (combining form of certus decided; certain ) + -ficāre -fy

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.

Boeing is working to certify the widebody jet for commercial service.

From Barron's • Feb. 19, 2026

Instead of going through the usual regulatory process, residents using federal emergency funds to rebuild would have to certify compliance with local standards.

From Los Angeles Times • Feb. 3, 2026

The company doesn’t generate significant sales yet as it works to certify its aircraft for commercial service.

From Barron's • Jan. 29, 2026

But charities have told BBC News employers will still be able to certify themselves without employing "a single disabled person".

From BBC • Jan. 15, 2026

“They will certify the results of this test before we make them public,” said Dr. Garcia.

From "The Smartest Kid in the Universe" by Chris Grabenstein