authenticate

/ɔ.ˈθɛn.tɪ.keɪt/

adjective

  1. Of the same origin as claimed; genuine.

    "The experts confirmed it was an authentic signature."

  2. Conforming to reality and therefore worthy of trust, reliance, or belief.

    "The report was completely authentic."

  3. (of a Gregorian mode) Having the final as the lowest note of the mode.

  4. Authoritative

Synonyms: credible, reliable, trustworthy, unfaked, bona fide, bonafide, genuine, real, unfaked
Antonyms: fake, ingenuine, phony

verb

  1. To render authentic; to give authority to, by the proof, attestation, or formalities required by law, or sufficient to entitle to credit.

  2. To prove authentic; to determine as real and true.

    "He didn't manage to authenticate the portrait: it's probably a fake."