apostate, bitter-ender, brawler, defendant, demurrer, diehard, disputant, dissenter, dissentient, dissident, intransigent, irreconcilable, last-ditcher, litigant, naysayer, negativist, nonconformist, noncooperator, obstructionist, obstructive, opinionist, opposer, opposition voice, oppositionist, plaintiff, protestant, protester, quarreler, recusant, resister, schismatic, scrapper, sectarian, sectary, separatist, wrangler