Beyond question or doubt. See Synonyms at authentic.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "unquestionable" in a sentence
"The Muslim prayer reminded me of what old-school Catholicism must have resembled — steeped in unquestionable tradition and inaccessibility, yet beautiful, a bit magical, and surreal."
"To suppress doubt, then, to discourage thinking, to try to stop a person from questioning the unquestionable is simply to make them more and more susceptible to the cynical, more unaccepting of naive belief."
"What was once unquestioned and unquestionable is now being questioned and doubted."