INEF'FABLE, adjective [Latin ineffabilis; in and effabilis, from effor, to speak.] Unspeakable; unutterable; that cannot be expressed in words; usually in a good sense; as the ineffable joys of heaven; the ineffable glories of the Deity.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI