The Collaborative International Dictionary of English v.0.48:
Ineffably \In*ef"fa*bly\, adv. In a manner not to be expressed in words; unspeakably. --Milton. [1913 Webster]WordNet (r) 3.0 (2006):
ineffably adv 1: 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" [syn: ineffably, indescribably, unutterably, unspeakably]