unutterable

adj

1. very difficult to pronounce correctly

e.g. an unpronounceable foreign word
unutterable consonant clusters

Synonym: unpronounceable

2. defying expression or description

e.g. indefinable yearnings
indescribable beauty
ineffable ecstasy
inexpressible anguish
unspeakable happiness
unutterable contempt
a thing of untellable splendor

Synonym: indefinableindescribableineffableunspeakableuntellable

3. too sacred to be uttered

e.g. the ineffable name of the Deity

Synonym: ineffableunnameableunspeakable

1. （尤指不好的事情）无以名状的，难以形容的，莫名的
You can use unutterable to emphasize that something, especially a bad quality, is great in degree or intensity.

e.g. I am at the beginning of a new and unutterable loneliness.
我再次陷入莫名的孤独寂寞中。
e.g. ...unutterable rubbish.
一派胡言

1. 非语言所能表达的：unusually /显着地/异常地/ | unutterable /非语言所能表达的/ | unutterably /非语言所能表达地/

2. 不可言传的：vulnerable 易受伤的,弱小的;易受...攻击的 | unutterable 不可言传的 | desirable 称心的,合意的,理想的