adjective (a)

• having a musical sound; especially a pleasing tune(adj.all)

  Synonym:
  tuneful
  Antonym:
  tuneless, unmelodious, untuneful
  

  source: wordnet30
• containing or constituting or characterized by pleasing melody(adj.all)

  Example:
  The melodious song of a meadowlark.
  

  Synonym:
  melodic, musical
  Antonym:
  unmelodic, unmelodious, unmusical
  

  source: wordnet30
• Containing, or producing, melody; musical; agreeable to the ear by a sweet succession of sounds; as, a melodious voice.(adjective)

  source: webster1913