in·su·per·a·ble 
/ɪnˈsu:pərəbəl, Brit ɪnˈsju:pərəbəl/ adjective
/ɪnˈsu:pərəbəl, Brit ɪnˈsju:pərəbəl/ adjective [more insuperable; most insuperable] formal, of a problem, difficulty, etc. : impossible to solve or get control of : impossible to overcome
▪ They succeeded despite some nearly insuperable [=insurmountable] difficulties. ▪ insuperable barriers
▪ They succeeded despite some nearly insuperable [=insurmountable] difficulties. ▪ insuperable barriers
