unquestionable

英[ʌn'kwestʃ(ə)nəb(ə)l] 美[ʌn'kwɛstʃənəbl]

1. impossible to question;

"unquestionable authority"

2. not counterfeit or copied;

"an authentic signature"

"a bona fide manuscript"

"an unquestionable antique"

"photographs taken in a veritable bull ring"

3. not open to question;

"an unquestionable (or unequivocal) loss of prestige"