undoubtable
Beyond all question
Undoubtable means not open to doubt; certain beyond question.
The word is rare, with *indubitable* and *undoubted* serving the same purpose more commonly: His talent is undoubtable.
The adverb *undoubtably* exists but is often considered an error for *undoubtedly*.
Impossible to deny
- irrefutableImpossible to disprove
- unquestionableCannot be challenged
- indisputableImpossible to contest
- absoluteTotal, without qualification
certain · positive · unassailable · evident · manifest · patent · obvious · clear-cut
Consistently performing as expected
- trustworthyWorthy of confidence
- dependableWorthy of trust
- credibleWorthy of acceptance
- authenticVerified as original
genuine · proven · faithful · consistent · accurate · verified · established · solid
Certain or self-possessed
- confidentSure of oneself
- convincedFirmly believing something
- secureProtected from harm
- unwaveringSteady and unchanging
unfaltering · steadfast · resolute · firm · decided · unhesitating · unshakeable · determined
Facts supporting truth
- verificationProving something accurate
- corroborationEvidence confirming another account
- validationConfirming truth or accuracy
- confirmationEstablishing something as true
substantiation · documentation · testimony · demonstration · authentication · certification · attestation · affirmation
incontrovertible
Impossible to deny
- irrefutableImpossible to disprove
- unquestionableCannot be challenged
- indisputableImpossible to contest
absolute · certain · positive · unassailable · evident · manifest · patent · obvious · clear-cut · self-evident
reliable
Consistently performing as expected
- trustworthyWorthy of confidence
- dependableWorthy of trust
- credibleWorthy of acceptance
authentic · genuine · proven · faithful · consistent · accurate · verified · established · solid · sound
assured
Certain or self-possessed
unwavering · unfaltering · steadfast · resolute · firm · decided · unhesitating · unshakeable · determined · knowing
evidence
Facts supporting truth
- verificationProving something accurate
- corroborationEvidence confirming another account
- validationConfirming truth or accuracy
confirmation · substantiation · documentation · testimony · demonstration · authentication · certification · attestation · affirmation · establishment