Source : Webster's Revised Unabridged Dictionary (1913)

Gladiator \Glad"i*a`tor\, n. [L., fr. gladius sword. See
   {Glaive}.]
   1. Originally, a swordplayer; hence, one who fought with
      weapons in public, either on the occasion of a funeral
      ceremony, or in the arena, for public amusement.

   2. One who engages in any fierce combat or controversy.

Source : WordNet®

gladiator
     n 1: (ancient Rome) a professional combatant or a captive who
          entertained the public by engaging in mortal combat
     2: a professional boxer [syn: {prizefighter}]