Formal:
* Unpleasant: This is a general term for something disagreeable.
* Rude: This implies a lack of good manners and consideration for others.
* Offensive: This suggests that the behavior or speech is likely to cause offense or upset.
* Insulting: This means the behavior or speech is intended to cause harm or belittle someone.
Informal:
* Mean: This is a common word for someone who is unkind and enjoys causing harm.
* Nasty: This implies something is unpleasant, offensive, or even dangerous.
* Spiteful: This means the behavior or speech is intended to cause harm or revenge.
* Vicious: This suggests a strong desire to cause harm, possibly with violence.
* Unkind: This is a general term for someone who is not compassionate or caring.
* Cruel: This is a more severe term for someone who enjoys causing pain or suffering.
Other options:
* Abusive: This suggests the behavior or speech is physically or emotionally harmful.
* Toxic: This is a modern term for someone who is consistently negative and destructive.
* Unpleasant: A more general term that signifies someone is disagreeable in their behavior or speech.
The best word to use will depend on the specific context and the severity of the behavior or speech.