A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Malignant cells can also spread to other parts of the body through the blood and lymph systems. Discover the meaning of ' malignant ', explore its usage in everyday language, popular idioms, and fun facts that make this word fascinating. Perfect for learners and curious minds! A term used to describe cancer. Malignant cells grow in an uncontrolled way and can invade nearby tissues and spread to other parts of the body through the blood and lymph system.