/ ʌnˈtʃælɪndʒəbl; NAmE / adjective
that cannot be questioned or argued with; that cannot be challenged :
unchallengeable evidence
/ ʌnˈtʃælɪndʒəbl; NAmE / adjective
that cannot be questioned or argued with; that cannot be challenged :
unchallengeable evidence
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005