DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Ruthless \Ruth"less\, a.
      Having no ruth; cruel; pitiless.
      [1913 Webster]
            Their rage the hostile bands restrain,
            All but the ruthless monarch of the main. --Pope.
      [1913 Webster] -- Ruth"less*ly, adv. -- Ruth"less*ness,
      n.
      [1913 Webster]