# malignant

/məˈɫɪɡnənt/ (US) · /məlˈɪɡnənt/ (UK)

Source: https://englishreference.com/word/malignant
Updated: 2026-08-08

## Senses

### 1. cancerous

adjective · CEFR C1 · Technical

used to describe a tumour or disease that is cancerous and can spread to other parts of the body.

For teachers: referring to a tumour that is invasive, tends to metastasize, and is likely to cause death if not treated.

- The doctors were relieved to find that the growth was not malignant.
- Biopsy results confirmed that the cells were malignant, necessitating an immediate and aggressive course of chemotherapy to prevent further spread.

Usage: Usually used to describe tumours, growths, or diseases.

### 2. evil or harmful

adjective · CEFR C2 · Literary · Formal

having a strong wish to do harm or cause suffering to others.

For teachers: characterised by intense ill will or a desire to cause deliberate harm; malevolent in nature.

- The villain in the story had a malignant influence on everyone he met.
- The dictator's malignant presence was felt throughout the country, as his policies slowly dismantled the foundations of civil society.

Teaching tip: In everyday English, 'evil' or 'harmful' are more common; reserve this for formal writing or describing a very deep, spreading kind of bad influence.

### 3. a harmful person

noun · CEFR C2 · Archaic · Formal

a person who is seen as dangerous or destructive to society.

For teachers: a person who is persistently hostile to a government or established authority; historically used for supporters of the king during the English Civil War.

- The old records described the rebels as dangerous malignants.
- Parliamentary forces sought to identify and punish the malignants who had remained loyal to the crown during the uprising.

## Examples

- The doctors confirmed that the tumor was malignant.
- The biopsy results showed that the growth was malignant, requiring immediate surgery and follow-up treatment.
- The dictator's malignant influence spread through the country, poisoning public discourse and turning neighbors against one another in an atmosphere of constant fear.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.