malignant
adjective
ma·lig·nant
mə-ˈlig-nənt 
1
: tending to produce death or deterioration
malignant malaria
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
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
The research also showed lower mortality risks from some forms of cancer and HIV and lower mortality rates for malignant neoplasms, HIV, and diabetes mellitus.
—Paul Smaglik, Discover Magazine, 12 Mar. 2025
Gliomas are often malignant, occasionally slow-growing brain cancers with significant rates of morbidity and mortality.
—New Atlas, 11 Mar. 2025
See All Example Sentences for malignant
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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
The research also showed lower mortality risks from some forms of cancer and HIV and lower mortality rates for malignant neoplasms, HIV, and diabetes mellitus.
—Paul Smaglik, Discover Magazine, 12 Mar. 2025
Gliomas are often malignant, occasionally slow-growing brain cancers with significant rates of morbidity and mortality.
—New Atlas, 11 Mar. 2025
See All Example Sentences for malignant
Cite this Entry
“Malignant.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/malignant. Accessed 4 May. 2025.
Copy CitationKids Definition
malignant
adjective
ma·lig·nant
mə-ˈlig-nənt
1
: evil in influence or effect : injurious
3
: tending to produce death
malignant tumors
malignantly
adverb
Medical Definition
malignant
adjective
ma·lig·nant
mə-ˈlig-nənt
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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