(n.) One who debates; one given to argument; a disputant; a controvertist.

Philadelphia lawyer apologist arguer argufier casuist controversialist declaimer demagogue disceptator disputant guardhouse lawyer haranguer jawsmith logomacher logomachist mooter panelist pilpulist polemic polemicist polemist public speaker rabble-rouser ranter speaker speecher speechifier speechmaker spieler spokesman spokeswoman spouter talker tub-thumper wrangler