Neutral:
* Debater: This is a common and neutral term for someone who engages in formal arguments.
* Disputant: This term is similar to "debater" but emphasizes the act of arguing.
* Contender: This word suggests someone who is willing to fight for their point of view.
Negative:
* Quibbler: Someone who argues about minor details or unimportant issues.
* Brawler: Someone who uses aggression and force when arguing.
* Scoffer: Someone who expresses derision or doubt.
* Contrarian: Someone who always takes the opposing view, even if it's not well-founded.
* Polemicist: Someone who engages in aggressive and often biased argumentation.
Positive:
* Advocate: Someone who argues for a cause or on behalf of another person.
* Champion: Someone who fights for what they believe in, often for a cause they are passionate about.
* Orator: Someone who is skilled in public speaking, often using persuasive arguments.
The best word to use depends on the specific context and the type of argumentation involved.