# diseased

/dɪˈzizd/ (US) · /dɪzˈiːzd/ (UK) · CEFR B2 · Adjective

Source: https://englishreference.com/word/diseased
Updated: 2026-05-08

## Definition

suffering from a physical or mental illness. You use this to describe a part of the body or a plant that is not healthy.

For teachers: suffering from or affected by a physical or mental illness. Often used to describe specific biological tissues or organs that have been compromised by infection or decay.

## Examples

- The gardener removed the diseased leaves from the rose bush.
- Doctors decided to operate immediately to remove the diseased tissue before the infection could spread further.
- The ancient elm tree, once a centerpiece of the village square, had to be felled after experts determined its diseased roots posed a significant safety risk.

## Pitfalls

- Not "the disease heart" but "the diseased heart" — Learners often use the noun 'disease' as a modifier instead of the participial adjective 'diseased'.

## Usage notes

- Typically used attributively before a noun; can also follow linking verbs like 'become' or 'look'.

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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.