1. 不能说的：duration 持续时间 | ineffable不能说的 | fable寓言

2. 不可言喻的;应该避讳的：Prolific 多育的,多产的 | Ineffable 不可言喻的;应该避讳的 | Mundane 世俗的,庸俗的

3. 无法表达的：affable 易于交谈的;和蔼的 | ineffable 无法表达的 | affection 感情

4. 妙不可言的,说不出的：inebriate 使醉,n. 酒鬼,酒徒 | ineffable 妙不可言的,说不出的 | ineffaceable 抹不掉的,不能消除的

1. 言语难以表达的;不可言喻的
You use ineffable to say that something is so great or extreme that it cannot be described in words.

e.g. ...the ineffable sadness of many of the portraits.
许多肖像流露出的难以形容的悲伤

adj

1. defying expression or description

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

Synonym: indefinableindescribableunspeakableuntellableunutterable

2. too sacred to be uttered

e.g. the ineffable name of the Deity

Synonym: unnameableunspeakableunutterable