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 2000, Norris Church Mailer was diagnosed with a malignant gastrointestinal tumor.
—
Arkansas Online, 28 Mar. 2026
Narratively, Daniel Craig’s returning lead Benoit Blanc takes a back pew to the conflict between a sensitive priest and a malignant monsignor who has turned away from Jesus’ teachings.
—Amy Nicholson, Los Angeles Times, 10 Mar. 2026
Over time, these polyps can become cancerous (malignant) and spread to other areas of the body.
—Alyssa Goldberg, USA Today, 12 Feb. 2026
The researchers found that this therapy prolonged survival in patients with glioblastoma, the most common and malignant primary brain tumor.
—Rick Sobey, Boston Herald, 11 Feb. 2026
See All Example Sentences for malignant
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Arkansas Online, 28 Mar. 2026
Narratively, Daniel Craig’s returning lead Benoit Blanc takes a back pew to the conflict between a sensitive priest and a malignant monsignor who has turned away from Jesus’ teachings.
—Amy Nicholson, Los Angeles Times, 10 Mar. 2026
Over time, these polyps can become cancerous (malignant) and spread to other areas of the body.
—Alyssa Goldberg, USA Today, 12 Feb. 2026
The researchers found that this therapy prolonged survival in patients with glioblastoma, the most common and malignant primary brain tumor.
—Rick Sobey, Boston Herald, 11 Feb. 2026
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 Apr. 2026.
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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