General terms:
* Insulter: This is the most straightforward and direct term.
* Abusive: This term implies a pattern of harsh, insulting language.
* Offensive: This term describes someone who makes remarks that are likely to cause offense.
More specific terms:
* Name-caller: Someone who uses insulting labels or derogatory terms.
* Slanderer: Someone who spreads false and damaging statements about another person.
* Defamer: Similar to a slanderer, but may also use written or visual means.
* Troll: Someone who intentionally provokes arguments or upsets people online, often through insults.
* Harasser: Someone who uses insulting and threatening language or behavior to intimidate or frighten someone.
* Bullying: This term usually refers to repeated insults, threats, or harassment directed towards someone perceived as weaker.
The best term to use will depend on the specific situation. For example, "insulter" might be appropriate for someone who makes occasional rude remarks, while "harasser" is more appropriate for someone who uses insulting language to intimidate another person.