1. malicious
2. nefarious
3. vicious
4. venom
5. virus
6. malignity
7. atrocity.
Examples:
1. 他對別人對他名聲的惡毒攻擊置之不理。
He cares nothing about the malicious attack on his reputation.
2. 那個編輯在壹篇社論中惡毒地攻擊了反對派。
The editor got his claws into the opposition in a vicious editorial.
3. 他惡毒的表情嚇壞了這個小女孩。
His venomous look terrified the little girl.
4. 惡毒或卑劣的行為
A spiteful or malicious act.