#1 unutterable s. [ineffable, unnameable, unspeakable] too sacred to be uttered; "the ineffable name of the Deity". wn
#2 unutterable s. [indefinable, indescribable, ineffable, unspeakable, untellable] defying expression or description; "indefinable yearnings"; "indescribable beauty"; "ineffable ecstasy"; "inexpressible anguish"; "unspeakable happiness"; "unutterable contempt"; "a thing of untellable splendor". wn
#3 unutterable s. [unpronounceable] very difficult to pronounce correctly; "an unpronounceable foreign word"; "unutterable consonant clusters". wn
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