Ineffable

In*ef"fa*ble (?), a. [L. ineffabilis: cf. F. ineffable. See In- not, and Effable, Fame.] Incapable of being expressed in words; unspeakable; unutterable; indescribable; as, the ineffable joys of heaven.

Contentment with our lot . . . will diffuse ineffable contentment over the soul.