Source : Webster's Revised Unabridged Dictionary (1913)

Playful \Play"ful\, a.
   Sportive; gamboling; frolicsome; indulging a sportive fancy;
   humorous; merry; as, a playful child; a playful writer. --
   {Play"ful*ly}, adv. -- {Play"ful*ness}, n.

Source : WordNet®

playful
     adj : full of fun and high spirits; "playful children sjust let
           loose from school" [ant: {unplayful}]