Open English Wordnet
Adjectives
(s)indefinable, indescribable, ineffable, unspeakable, untellable, unutterabledefying expression or description“indefinable yearnings”, “indescribable beauty”, “ineffable ecstasy”, “unspeakable happiness”, “unutterable contempt”, “a thing of untellable splendor”
(s)ineffable, unnameable, unspeakable, unutterabletoo sacred to be uttered“the ineffable name of the Deity”