malignant
Definitions
Characterized by uncontrolled growth and the tendency to spread, as in a cancerous tumor.
Malevolent or spiteful in nature, influence, or effect.
Examples
The doctor performed a biopsy to determine if the tumor was malignant or benign.
His malignant influence over the group eventually led to its complete collapse.
Synonyms
harmful malevolent virulent pernicious cancerous deadly malicious