General synonyms:
* Arguer
* Debater
* Opponent
* Contender
* Adversary
* Controversialist
More specific synonyms:
* Litigant: This term specifically refers to a person involved in a legal dispute.
* Antagonist: This implies a strong opposition or hostility in the argument.
* Challenger: This emphasizes the act of questioning or taking issue with something.
* Polemicist: This refers to someone who engages in strong and often bitter arguments, especially on religious or political issues.
* Quibbler: This implies someone who finds fault with minor details or uses petty arguments.
Informal synonyms:
* Bickerer: This describes someone who engages in petty arguments.
* Squabbler: This is a more informal term for someone who argues frequently.
* Grumbler: This suggests someone who complains or expresses dissatisfaction.
The best synonym for "disputant" depends on the context of your sentence and the specific type of argument you want to describe.