The Collaborative International Dictionary of English v.0.48:
Everlastingly \Ev`er*last"ing*ly\, adv. In an everlasting manner. [1913 Webster]WordNet (r) 3.0 (2006):
everlastingly adv 1: for a limitless time; "no one can live forever"; "brightly beams our Father's mercy from his lighthouse evermore"- P.P.Bliss [syn: everlastingly, eternally, forever, evermore]