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®

harmless
     adj 1: not causing or capable of causing harm; "harmless bacteria";
            "rendered the bomb harmless" [ant: {harmful}]
     2: not injurious to physical or mental health [syn: {innocuous}]
        [ant: {noxious}]
     3: not producing any toxic effects
     4: unlikely to harm or disturb anyone; "harmless old man" [syn:
         {innocuous}]
     5: not threatening to life or health; not malignant; "a benign
        tumor is usually harmless" [syn: {nonmalignant}]