The Collaborative International Dictionary of English v.0.48:

Sportive \Sport"ive\ (-[i^]v), a.
   Tending to, engaged in, or provocative of, sport; gay;
   frolicsome; playful; merry.
   [1913 Webster]

         Is it I
         That drive thee from the sportive court? --Shak.
   [1913 Webster] -- Sport"ive*ly, adv. -- Sport"ive*ness,
   n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sportiveness
    n 1: lively high-spirited playfulness [syn: friskiness,
         frolicsomeness, sportiveness]