The Collaborative International Dictionary of English v.0.48:

Warrior \War"rior\ (?; 277), n. [OE. werreour, OF. werreour,
   guerreor, from guerre, werre, war. See War, and Warray.]
   A man engaged or experienced in war, or in the military life;
   a soldier; a champion.
   [1913 Webster]

         Warriors old with ordered spear and shield. --Milton.
   [1913 Webster]

   Warrior ant (Zool.), a reddish ant (Formica sanguinea)
      native of Europe and America. It is one of the species
      which move in armies to capture and enslave other ants.
      [1913 Webster]

WordNet (r) 3.0 (2006):

warrior
    n 1: someone engaged in or experienced in warfare