Definition of "malignant" []

• Showing great malevolence; disposed to do evil. (adjective)
• Highly injurious; pernicious. (adjective)
• Pathology Threatening to life; virulent: a malignant disease. (adjective)
• Pathology Tending to metastasize; cancerous. Used of a tumor. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "_malignant_ and _poisonous_ affections, as scirrhus and other varieties of cancer, and also cases of infectious virus, demand continually, or with but occasional exceptions, the primary galvanic current A B. ☞ In treating these malignant affections, the current should be run through as short a distance of _healthy_ tissue as possible, yet so as fairly to reach the diseased part."
• "‡ The term malignant is used in describing cancerous tumors (see cancer) because such growths are a threat to the health of the individual."
• "Congressman Foley is the poster child for what we call malignant narcissism."