malignant

adjective

ma·​lig·​nant mə-ˈlig-nənt How to pronounce malignant (audio)
1
: tending to produce death or deterioration
malignant malaria
especially : tending to infiltrate, metastasize, and terminate fatally
a malignant tumor
2
a
: 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
malignantly adverb

Examples of malignant in a Sentence

a highly malignant form of cancer a powerful and malignant influence
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Last month, my son reached two years in remission from a rare, malignant cancer that almost took his eye and his life. Dayna Copeland, The Mercury News, 15 Mar. 2025 After a series of tests, Karen was diagnosed with a glioma of the pons, a malignant tumor growing within the middle part of her brain stem. Jackie Tempera, People.com, 27 Apr. 2025 In 2024, Tina Knowles, 71, underwent a lumpectomy to have the malignant tumor removed. Sara Vallone, Miami Herald, 22 Apr. 2025 Based on breast imaging, AI tools can be used to better predict if a lesion is malignant and support clinical decision making. Eyal Shamir, Forbes, 14 Mar. 2025 See All Example Sentences for malignant

Word History

Etymology

Late Latin malignant-, malignans, present participle of malignari

First Known Use

1542, in the meaning defined at sense 2c

Time Traveler
The first known use of malignant was in 1542

Browse Nearby Words

Cite this Entry

“Malignant.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/malignant. Accessed 23 May. 2025.

Kids Definition

malignant

adjective
ma·​lig·​nant mə-ˈlig-nənt How to pronounce malignant (audio)
1
: evil in influence or effect : injurious
2
3
: tending to produce death
malignant tumors
malignantly adverb

Medical Definition

malignant

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

More from Merriam-Webster on malignant

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