The Collaborative International Dictionary of English v.0.48:
Cacophonic \Cac`o*phon"ic\, Cacophonical \Cac`o*phon"ic*al\, Cacophonous \Ca*coph"o*nous\, Cacophonious \Cac`o*pho"ni*ous\, a. Harsh-sounding. [1913 Webster]WordNet (r) 3.0 (2006):
cacophonous adj 1: having an unpleasant sound; "as cacophonous as a henyard"- John McCarten [syn: cacophonous, cacophonic] [ant: euphonious, euphonous]