The Collaborative International Dictionary of English v.0.48:

Wrangler \Wran"gler\, n.
   1. An angry disputant; one who disputes with heat or
      peevishness. "Noisy and contentious wranglers." --I.
      Watts.
      [1913 Webster]

   2. One of those who stand in the first rank of honors in the
      University of Cambridge, England. They are called,
      according to their rank, senior wrangler, second wrangler,
      third wrangler, etc. Cf. Optime.
      [1913 Webster]

WordNet (r) 3.0 (2006):

wrangler
    n 1: someone who argues noisily or angrily
    2: a cowboy who takes care of the saddle horses [syn: horse
       wrangler, wrangler]

Moby Thesaurus II by Grady Ward, 1.0:

127 Moby Thesaurus words for "wrangler":
   Philadelphia lawyer, apologist, arguer, argufier, battler,
   belligerent, belted knight, bickerer, bitter-ender, blade, bravo,
   brawler, bully, bullyboy, casuist, cattleman, combatant, commoner,
   competitor, contender, contestant, controversialist, cowboy,
   cowgirl, cowhand, cowherd, cowman, cowpuncher, debater, defendant,
   diehard, disceptator, disputant, dissentient, dissident, drover,
   duelist, enforcer, exhibitioner, fencer, feuder, fighter,
   fighting cock, foilsman, gamecock, gaucho, gladiator, goatherd,
   goon, gooseboy, gooseherd, gorilla, guardhouse lawyer, hatchet man,
   herder, herdsman, hogherd, hood, hoodlum, hooligan, horse wrangler,
   horseherd, intransigent, irreconcilable, jouster, knight,
   last-ditcher, litigant, logomacher, logomachist, militant, mooter,
   naysayer, negativist, noncooperator, objector, obstructionist,
   obstructive, opposer, oppositionist, optime, passman, pensioner,
   pigman, pilpulist, plaintiff, plug-ugly, polemic, polemicist,
   polemist, protester, puncher, quarreler, questionist, resister,
   rioter, rival, rough, rowdy, ruffian, sabreur, scrapper, scuffler,
   servitor, sheepherder, sheepman, shepherd, shepherdess, sizar,
   sophister, squabbler, strong arm, strong-arm man, strong-armer,
   struggler, swanherd, swashbuckler, swineherd, sword, swordplayer,
   swordsman, thug, tilter, tough, tussler, vaquero, waddy