Disputant

Noun

 * 1) A participant in a dispute.
 * 2) * 1893, Henry James, Collaboration
 * One of the liveliest scenes of the performance was the evening, last winter, on which I became aware that one of my compatriots – an American, my good friend Alfred Bonus – was engaged in a controversy somewhat acrimonious, on a literary subject, with Herman Heidenmauer, the young composer who had been playing to us divinely a short time before and whom I thought of neither as a disputant nor as an Englishman.

Adjectives
scientific; forensic; obstinate; moral; voiceless ; excited.

Thesaurus
Philadelphia lawyer, apologist, arguer, argufier, battler, belligerent, belted knight, bickerer, bitter-ender, blade, bravo, brawler, bully, bullyboy, casuist, combatant, competitor, contender, contestant, controversialist, debater, defendant, diehard, disceptator, dissentient, dissident, duelist, enforcer, fencer, feuder, fighter, fighting cock, foilsman, gamecock, gladiator, goon, gorilla, guardhouse lawyer, hatchet man, hood, hoodlum, hooligan, intransigent, irreconcilable, jouster, knight, last-ditcher, litigant, logomacher, logomachist, militant, mooter, naysayer, negativist, noncooperator, objector, obstructionist, obstructive, opposer, oppositionist, pilpulist, plaintiff, plug-ugly, polemic, polemicist, polemist, protester, quarreler, resister, rioter, rival, rough, rowdy, ruffian, sabreur, scrapper, scuffler, squabbler, strong arm, strong-arm man, strong-armer, struggler, swashbuckler, sword, swordplayer, swordsman, thug, tilter, tough, tussler, wrangler

Verb
disputant