INEFFABLY
ineffably, indescribably, unutterably, unspeakably, inexpressibly
(adverb) to an inexpressible degree; “she was looking very young tonight, and, as usual, indescribably beautiful, in a simple strapless dress of a green and white silky cotton”
Source: WordNet® 3.1
Etymology
Adverb
ineffably (comparative more ineffably, superlative most ineffably)
indescribably; to a very great degree or extent.
unmentionably; unspeakably
The name of God is ineffably holy.
Source: Wiktionary
In*ef"fa*bly, adv.
Definition: In a manner not to be expressed in words; unspeakably. Milton.
INEFFABLE
In*ef"fa*ble, a. Etym: [L. ineffabilis: cf. F. ineffable. See In-
not, and Effable, Fame.]
Definition: Incapable of being expresses in words; unspeakable;
unutterable; indescribable; as, the ineffable joys of heaven.
Contentment with our lot . . . will diffuse ineffable contenBeattie.
Source: Webster’s Unabridged Dictionary 1913 Edition