The Collaborative International Dictionary of English v.0.48:

Joyful \Joy"ful\, a.
   Full of joy; having or causing joy; very glad; as, a joyful
   heart. "Joyful tidings." --Shak.
   [1913 Webster]

         My soul shall be joyful in my God.       --Is. lxi. 10.
   [1913 Webster]

         Sad for their loss, but joyful of our life. --Pope.
   -- Joy"ful*ly, adv. -- Joy"ful*ness, n.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

joyfulness \joyfulness\ n.
   the emotion of great happiness.

   Syn: joy, joyousness.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

joyfulness
    n 1: the emotion of great happiness [syn: joy, joyousness,
         joyfulness] [ant: sorrow]