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.
Shortly after his birth, doctors discovered fluid building up inside the baby boy's head in addition to a malignant tumor that required brain surgery. Hannah Sacks, People.com, 23 June 2025 Nevertheless, case reports have described malignant tumors developing within tattoos, including melanomas. Jesse Pines, Forbes.com, 13 June 2025 In this sense, madness is a bit like the radical-feminist conception of gender itself: a malignant force whose power is intimate yet strangely impersonal. Moira Donegan, New Yorker, 26 Mar. 2025 In healthcare, for example, AI is being used in skin cancer detection, yet studies show that dermatologists are less likely to recommend biopsies for malignant skin cancers on patients with darker skin. Pauleanna Reid, Forbes.com, 18 June 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 7 Jul. 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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