ineffable

形容词 ineffable:

1. defying expression or description
   同义词：indefinable, indescribable, unspeakable, untellable, unutterable
2. too sacred to be uttered
   同义词：unnameable, unspeakable, unutterable

1. The ineffable name of the Deity.
   神的名字是忌讳说的

in.ef.fa.ble

adj.（形容词）
Incapable of being expressed; indescribable or unutterable.See Synonyms at unspeakable
不可言喻的：难以表达的；难以描叙的参见 unspeakable
Not to be uttered; taboo:
避讳的：不能说的；禁忌的：
例句：
the ineffable name of the Deity.
神的名字是忌讳说的

来源：
Middle English
中古英语
from Old French
源自 古法语
from Latin ineff3bilis
源自 拉丁语 ineff3bilis
in- [not] * see in-
in- [不] *参见 in-
eff3bilis [utterable] from eff3ro [to utter] ex- [ex-] f3ro [to speak] * see bh3- 2
eff3bilis [可说出的] 源自 eff3ro [说] ex- [前缀，表示.发出.] f3ro [说] *参见 bh3- 2

【引伸】
inef.fabil.ity 或
inef.fableness
n.（名词）
inef.fably
adv.（副词）