ma·​lig·​nant | \ mə-ˈlig-nənt How to pronounce malignant (audio) \

Definition of malignant

1 : tending to produce death or deterioration malignant malaria especially : tending to infiltrate, metastasize, and terminate fatally a malignant tumor
2a : evil in nature, influence, or effect : injurious a powerful and malignant influence
b : passionately and relentlessly malevolent : aggressively malicious the malignant tongues of gossipers
c obsolete : malcontent, disaffected

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Other Words from malignant

malignantly adverb

Examples of malignant in a Sentence

a highly malignant form of cancer a powerful and malignant influence
Recent Examples on the Web The Cincinnati police union has raised thousands of dollars for the family of an officer who is recovering after having a malignant brain tumor surgically removed. Quinlan Bentley, The Enquirer, "Police union raises thousands for officer recovering from brain cancer," 29 Apr. 2021 Shortly after that, doctors found a malignant tumor near Brown's pancreas. Jeff Potrykus, Milwaukee Journal Sentinel, "'My parents raised me to fight': UW's new running backs coach shares wisdom from his two bouts with cancer," 12 Apr. 2021 In the real world, not within baseball’s metrics but rather their own personal nightmares, Mancini was felled by a stunning spring diagnosis of Stage 3 colon cancer, the removal of a malignant tumor, the hell of chemotherapy. Gabe Lacques, USA TODAY, "'My body was all chills': Eduardo Rodriguez, Trey Mancini moved by receptions after COVID-19, cancer battles," 9 Apr. 2021 The 29-year-old Mancini wasn’t feeling well all spring training in 2020, and tests eventually found a malignant tumor in his colon. Jon Meoli,, "Orioles’ Trey Mancini savors Opening Day return: ‘I made sure to soak it all in’," 2 Apr. 2021 Stopping cheating cells is not an easy task, because, in an ironic twist, malignant cells that stop cooperating with normal cells can start to cooperate with one another. Athena Aktipis, Scientific American, "How Evolution Helps Us Understand Cancer and Control It," 1 Jan. 2021 Malvin declared that racial discrimination was a malignant human invitation that violated the laws of God and nature. Kate Masur, Smithsonian Magazine, "Decades Before the Civil War, Black Activists Organized for Racial Equality," 24 Mar. 2021 On the opposite side of the musical spectrum, the film has Mrs. Litvak (Lynn Cohen), the mentally-declining wife of the deceased man, who vacillates between malignant and benign throughout the runtime. Josh Weiss, Forbes, "‘The Vigil’: Why Michael Yezerski Avoided Klezmer Influence For His Haunting Score," 9 Mar. 2021 Mancini had surgery to remove a malignant tumor on March 12, 2020 and had six months of chemotherapy that end in September. Jon Meoli,, "Orioles observations on Trey Mancini’s first home run of the spring, hot-hitting Austin Hays, and more," 19 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'malignant.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of malignant

1542, in the meaning defined at sense 2c

History and Etymology for malignant

Late Latin malignant-, malignans, present participle of malignari

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Time Traveler for malignant

Time Traveler

The first known use of malignant was in 1542

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Statistics for malignant

Last Updated

4 May 2021

Cite this Entry

“Malignant.” Dictionary, Merriam-Webster, Accessed 11 May. 2021.

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More Definitions for malignant



English Language Learners Definition of malignant

medical : very serious and dangerous : tending or likely to grow and spread in a rapid and uncontrolled way that can cause death
formal : very evil


ma·​lig·​nant | \ mə-ˈlig-nənt How to pronounce malignant (audio) \

Kids Definition of malignant

1 : malicious
2 : likely to cause death : deadly

Other Words from malignant

malignantly adverb


ma·​lig·​nant | \ mə-ˈlig-nənt How to pronounce malignant (audio) \

Medical Definition of malignant

1 : tending to produce death or deterioration malignant malaria especially : tending to infiltrate, metastasize, and terminate fatally malignant tumors — compare benign sense 1
2 : of unfavorable prognosis : not responding favorably to treatment psychotic reactions with a malignant trend

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