Word family noun challenge challenger adjective challenging challenged ≠ unchallenged unchallengeable verb challenge adverb challengingly
From Longman Dictionary of Contemporary Englishunchallengeableun‧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 evidence2 if someone’s power or authority is unchallengeable, it cannot be taken from themExamples from the Corpus
unchallengeable• As his mouth opened, Alan saw the gaps in his teeth, but his voice and his movements seemed unchallengeable.• The assertion that some particular type of conduct is morally wrong because it is may appear unsatisfactory but it is unchallengeable.• When the procedure is correctly observed it is virtually unchallengeable.• Certain principles and values are assumed to be unchallengeable and therefore to be nurtured.• And even if, I repeat their findings were valid, enough unchallengeable evidence would remain to make them immaterial.• By contrast, the appeal of the industrial co-operative remains unchallengeable, its ecological niche exclusive to it.• Many leading scientists do not consider that science can give absolutely reliable and unchallengeable knowledge.• Indeed little of what had been unchallengeable orthodoxy since the 1920s remained untouched. 