Source : Webster's Revised Unabridged Dictionary (1913)

Wantonly \Wan"ton*ly\, adv.
   1. In a wanton manner; without regularity or restraint;
      loosely; sportively; gayly; playfully; recklessly;
      lasciviously.

   2. Unintentionally; accidentally. [Obs.] --J. Dee.

Source : WordNet®

wantonly
     adv 1: in a wanton manner; "the animals were killed wantonly for
            sport"
     2: in a licentious and promiscuous manner; "this young girl has
        to share a room with her mother who lives promiscuously"
        [syn: {licentiously}, {promiscuously}]