MALIG'NANT, adjective [Latin malignus, maligno, from malus, evil.] 1. Malicious; having extreme malevolence or enmity; as a malignant heart. 2. Unpropitious; exerting pernicious influence; as malignant start. 3. Virulent; as a malignant ulcer. 4. Dangerous to life; as a malignant fever. 5. Extremely heinous; as the malignant nature of sin. MALIG'NANT, noun A man of extreme enmity or evil intentions. [Not used.]
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI