Source : Webster's Revised Unabridged Dictionary (1913)

Harmless \Harm"less\, a.
   1. Free from harm; unhurt; as, to give bond to save another
      harmless.

   2. Free from power or disposition to harm; innocent;
      inoffensive. `` The harmless deer.'' --Drayton

   Syn: Innocent; innoxious; innocuous; inoffensive;
        unoffending; unhurt; uninjured; unharmed.
        --{Harm"less*ly}, adv.- {Harm"less*ness}, n.

Source : WordNet®

harmlessly
     adv : in a harmless manner; "this is a harmlessly childish game"
           [ant: {detrimentally}]