The Collaborative International Dictionary of English v.0.48:

Batteler \Bat"tel*er\, Battler \Bat"tler\, n. [See 2d Battel,
   n.]
   A student at Oxford who is supplied with provisions from the
   buttery; formerly, one who paid for nothing but what he
   called for, answering nearly to a sizar at Cambridge.
   --Wright.
   [1913 Webster]

WordNet (r) 3.0 (2006):

battler
    n 1: someone who fights (or is fighting) [syn: combatant,
         battler, belligerent, fighter, scrapper]