From Longman Dictionary of Contemporary English un‧chal‧lenge‧a‧ble /ʌnˈtʃæləndʒəbəl/ adjective 1 a belief, idea etc that is unchallengeable is definitely true and cannot be questioned or argued with unchallengeable evidence 2 if someone’s power or authority is unchallengeable, it cannot be taken from them Examples from the Corpus unchallengeable • As his mouth opened, Alan saw the gaps in his teeth, but his voice and his...