English Reference

Word

diseased

Phoneticsdis·eased

US/dɪˈzizd/

UK/dɪzˈiːzd/

Definition

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

adj. 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.”

Examples

simple

“The gardener removed the diseased leaves from the rose bush.”

contextual

“Doctors decided to operate immediately to remove the diseased tissue before the infection could spread further.”

complex

“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.”

Usage

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

Pitfall

the disease heart

the diseased heart

Learners often use the noun 'disease' as a modifier instead of the participial adjective 'diseased'.

Real-World Examples

“The fungus remained present in similar quantities in the soil of both diseased and healthy plants.”
Phys.org · 24 Aug 2026
“We also sequenced both tumors and healthy tissue in the diseased fish.”
Phys.org · 19 Aug 2026

Etymology

* disease + -ed

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry

Level
B2 · Upper Intermediate
Frequency
Occasional
Updated

Scan code

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English Reference