adjective

malignant

/məˈlɪɡnənt/ · say it: muh·LIG·nuhnt

cancerous and able to spread

In Medicine & Health

In more detail

1. (adjective) (of a disease, especially cancer) very serious and likely to cause death

2. (adjective) (of a person or their behavior) evil or harmful; wishing to cause harm to others

Examples

1. The doctor diagnosed her with a malignant tumor that required immediate surgery.
2. He had a malignant personality and enjoyed hurting people's feelings.

How to use malignant

Malignant is used in medical contexts to describe cancers and diseases that are aggressive and life-threatening, contrasting with benign conditions. In non-medical contexts, it describes people, motives, or influences that are deliberately harmful or evil, carrying a stronger moral condemnation than simply 'bad'. It suggests not just harmfulness but active ill intent.

Common phrases

malignant tumor
malignant cancer
malignant influence
malignant intent
malignant growth

Synonyms

cancerous · deadly · virulent · pernicious · malevolent

Opposites

benign · harmless · kind

Word family

malignancy (noun) · malignantly (adverb) · malign (verb/adjective)

A common mistake

Learners sometimes confuse malignant with malicious; while related, malignant emphasizes inherent danger or severity whereas malicious emphasizes deliberate intention to harm.

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