Source : WordNet®

untellable
     adj : defying expression or description; "indefinable yearnings";
           "indescribable beauty"; "ineffable ecstasy";
           "inexpressible anguish"; "unspeakable happiness";
           "unutterable contempt"; "a thing of untellable
           splendor" [syn: {indefinable}, {indescribable}, {ineffable},
            {unspeakable}, {unutterable}]