unquestionable
adjective
1. incapable of being questioned
- unquestionable authority
Similar word(s): incontestable, incontestible, undeniable, acknowledged, indubitable, mathematical, unimpeachable
2. not counterfeit or copied
- an unquestionable antique
Similar word(s): echt, genuine, authentic, veritable
3. not open to question
- an unquestionable (or unequivocal) loss of prestige
Similar word(s): unambiguous, unequivocal, univocal