unspeakable

defying expression or description; "indefinable yearnings"; "indescribable beauty"; "ineffable ecstasy"; "inexpressible anguish"; "unspeakable happiness"; "unutterable contempt"; "a thing of untellable splendor"

exceptionally bad or displeasing; "atrocious taste"; "abominable workmanship"; "an awful voice"; "dreadful manners"; "a painful performance"; "terrible handwriting"; "an unspeakable odor came sweeping into the room"

too sacred to be uttered; "the ineffable name of the Deity"