(a.) Ineffable; unspeakable; indescribable; unutterable; as, inexpressible grief or pleasure\.

awesome awful divine heavenly holy incommunicable indefinable indescribable ineffable inenarrable innominable inviolable inviolate noncommunicable numinous religious sacred sacrosanct spiritual undefinable unmentionable unnameable unspeakable untellable untouchable unutterable unwhisperable venerable