Extremely poisonous or venomous; very active in doing injury.
- Extremely infectious, malignant, or poisonous. Used of a disease or toxin.
- Capable of causing disease by breaking down protective mechanisms of the host. Used of a pathogen.
- Bitterly hostile or antagonistic; hateful: virulent criticism. See Synonyms at poisonous.
- Intensely irritating, obnoxious, or harsh.