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