General nastiness:
* Snide: Implying something unpleasant or insulting in a subtle way.
* Sarcastic: Using irony or mockery to convey contempt.
* Condescending: Treating someone as if they are inferior or foolish.
* Scornful: Expressing deep contempt or disdain.
* Vicious: Cruel and intended to cause harm.
Specific tone:
* Bitter: Expressing deep resentment or anger.
* Caustic: Harsh and sarcastic.
* Acerbic: Sharp, biting, and critical.
* Sardonic: Mocking and cynical.
* Scathing: Severely critical and hurtful.
Other words:
* Insulting: Offensive and disrespectful.
* Abusive: Using harsh language and threats.
* Rude: Discourteous and impolite.
* Venomous: Full of malice and spite.
The best word to use will depend on the specific context and the intended meaning.