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

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

Synonyms

• bad [slang]
• bitchy
• catty
• cruel
• despiteful
• hateful
• malevolent
• malicious
• malign
• mean
• nasty
• spiteful
• vicious
• virulent

Examples of malignant in a Sentence

a highly malignant form of cancer

a powerful and malignant influence

Recent Examples on the Web

She’s also undergone 30 cryogenic lung ablations—a procedure in which a radiologist uses a needle-like probe to freeze malignant tumors off the lungs. —Julia Ries, SELF, 4 Dec. 2024

While the diverse kinds of grants from the Institute of Museum and Library Services or Energy Department loan programs may not immediately seem representative of the sub-regulatory decrees that irk industry, increasingly the malignant materiality and significance of grants deserve more attention. —Clyde Wayne Crews Jr., Forbes, 30 Oct. 2024

Her freshman year at USC was cut short in October 2023 after having emergency surgery to remove a large medulloblastoma — a type of malignant tumor — in her cerebellum. —Vanessa Etienne, People.com, 20 Nov. 2024

Their administration has spent years appeasing Iran with sanctions relief and turning a blind eye to the malignant activity of the regime and its proxies. —The Editors, National Review, 4 Sep. 2024

Word History

Etymology

Late Latin malignant-, malignans, present participle of malignari

First Known Use

1542, in the meaning defined at sense 2c

Phrases Containing malignant

• malignant melanoma

Kids Definition

malignant

adjective

ma·​lig·​nant mə-ˈlig-nənt 

1

: evil in influence or effect : injurious

2

: malicious sense 1

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