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
One 2021 systematic review found that among postmenopausal women whose endometriosis did become malignant, about 75% had used estrogen-only MHT.
—
Tabitha Britt, Flow Space, 29 Oct. 2025
There are also skin diseases, such [as] autoimmune diseases like lupus erythematosus or malignant lymphoma, that are featured as chronic panniculitis clinically.
—Jasmine Laws, MSNBC Newsweek, 27 Oct. 2025
Some of the images contain cancerous tumors, and, over time, the AI learns to distinguish the often subtle differences between malignant and benign tissue.
—Elizabeth Cohen, NBC news, 22 Oct. 2025
These malignant tumors are often hormone receptor-positive, meaning the cancer cells grow in response to estrogen or progesterone.
—Faye Chiu, CNN Money, 22 Oct. 2025
See All Example Sentences for malignant
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Tabitha Britt, Flow Space, 29 Oct. 2025
There are also skin diseases, such [as] autoimmune diseases like lupus erythematosus or malignant lymphoma, that are featured as chronic panniculitis clinically.
—Jasmine Laws, MSNBC Newsweek, 27 Oct. 2025
Some of the images contain cancerous tumors, and, over time, the AI learns to distinguish the often subtle differences between malignant and benign tissue.
—Elizabeth Cohen, NBC news, 22 Oct. 2025
These malignant tumors are often hormone receptor-positive, meaning the cancer cells grow in response to estrogen or progesterone.
—Faye Chiu, CNN Money, 22 Oct. 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 1 Nov. 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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