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Synonyms for Unutterable (same or very similar meaning)

WordNet sense 1 (too sacred to be uttered):
ineffable, unnameable, unspeakable

WordNet sense 2 (concerned with religion or religious purposes):

WordNet sense 3 (defying expression or description):
indefinable, indescribable, untellable

WordNet sense 4 (defying expression):
inexpressible, unexpressible

WordNet sense 5 (very difficult to pronounce correctly):

WordNet sense 6 (not inclined to talk or give information or express opinions):
uncommunicative, incommunicative

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