unutterable

/ˈʌnˌʌdərəbəl/

Anything that's just too horrible to say out loud is unutterable. Waking in unutterable fear from a nightmare makes it hard to fall back to sleep again.

Intense feelings tend to be unutterable, whether it's your profound sorrow at the death of your cat or your unspeakable urge to strangle your sister from time to time. This adjective is ideal for describing things that can't be uttered, or expressed in words, from a root meaning "out." During the Victorian era, it was thought by many to be vulgar to talk about pants or trousers, and some people used euphemisms instead — including calling them unutterables.

Definitions of unutterable

1. adjective

   too sacred to be uttered
   synonyms: ineffable, unnameable, unspeakable

   sacred

   concerned with religion or religious purposes
2. adjective

   defying expression or description
   “unutterable contempt”

   synonyms: indefinable, indescribable, ineffable, unspeakable, untellable

   inexpressible, unexpressible

   defying expression
3. adjective

   very difficult to pronounce correctly
   “unutterable consonant clusters”

   synonyms: unpronounceable

   incommunicative, uncommunicative

   not inclined to talk or give information or express opinions