| malignant |
| 1. adj. Harmful, malevolent, injurious. | |
| malignant temper; malignant revenge; malignant infection | |
| 2. adj. (medicine) Tending to produce death; threatening a fatal issue. | |
| malignant diphtheria | |
| a malignant tumor | |
| 3. n. A deviant; a person who is hostile or destructive to society. | |
| 4. n. (historical, derogatory, obsolete) A person who fought for Charles I in the English Civil War. | |
| virulent |
| 1. adj. (chiefly medicine, of a disease or disease-causing agent) Highly infectious, malignant or deadly. | |
| 2. adj. Hostile to the point of being venomous; intensely acrimonious. | |
| The politicians were virulent in their hatred of the president. | |
| spiteful |
| 1. adj. Filled with, or showing, spite; having a desire to annoy or harm. | |
