WordWeb Online

1. Full of or producing joy
   "make a joyful noise"; "a joyful occasion"
    
2. Full of high-spirited delight
   "a joyful heart";
   - elated, gleeful, jubilant, cock-a-hoop [informal], gleesome [archaic], on top of the world [informal]

See also: beatific, happy, joyous, on cloud nine [informal], overjoyed

Antonym: sorrowful

Encyclopedia: Joyful, Joyful We Adore Thee