superunbelievable /ˌsuːpəˈɹˌʌnbəˈliːvəbl̩/ adjective1 •(rare) Extraordinarily unbelievable; of exceptional unbelievability or unbelievableness.Superunbelievable: There is little that I can say that has not already been said by the press and listener reviews. — 2012 formsmore superunbelievable · most superunbelievable