a. Not utterable; incapable of being spoken or voiced; inexpressible; ineffable; unspeakable; as, unutterable anguish. [ 1913 Webster ]
Sighed and looked unutterable things. Thomson. [ 1913 Webster ]
-- Un*ut"ter*a*ble*ness, n. -- Un*ut"ter*a*bly, adv. [ 1913 Webster ]