Part of speech:
That cannot be described; beyond the power of description
The definition of incredible is something so unbelievable or so unusual that it is hard to believe.
Not to be uttered; taboo:
The definition of remarkable is something unusual, extraordinary or worthy of attention.
That cannot be defined
That cannot be described
Not fit to be mentioned.
Not to be named or identified:
Find another word for unutterable. In this page you can discover 20 synonyms, antonyms, idiomatic expressions, and related words for unutterable, like: indescribable, incredible, ineffable, undescribable, remarkable, impossible, unbelievable, unspeakable, incommunicable, indefinable and inexpressible.