insuperable
From Longman Dictionary of Contemporary Englishinsuperablein‧su‧pe‧ra‧ble /ɪnˈsjuːpərəbəl◂ $ ɪnˈsuː-/ adjective formal IMPOSSIBLEan insuperable difficulty or problem is impossible to deal with There were insuperable obstacles, and the plan was abandoned. As usual, the hero was facing insuperable odds.Examples from the Corpusinsuperable• The legal barriers are presently insuperable.Origin insuperable (1300-1400) French Latin, from superare “to get over”, from super “above”