[1] : The Collaborative International Dictionary of English v.0.48

debater \debat"er\, n.
   one who debates; one given to argument; a disputant; a
   controvertist.
   1913 webster

         debate where leisure serves with dull debaters. --shak.
   1913 webster

[2] : WordNet (r) 2.0

debater
     n : someone who engages in debate syn: arguer
see also:
arguer 

[3] : Moby Thesaurus II by Grady Ward, 1.0

35 moby thesaurus words for "debater":
   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

Debater >> D Words
Debater, definition of term: Debater
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