diseased
Americanadjective
adjective
Other Word Forms
Etymology
Origin of diseased
1425–75; late Middle English disesed; compare Anglo-French diseasé. See disease, -ed 2
Explanation
When something is unhealthy or affected by illness, it's diseased. Sadly, the diseased trees in the city park may eventually need to be cut down and removed. While this adjective essentially means "sick," it's not generally used to describe people. Instead, you might use it for plants, animals, or body parts: "Hepatitis can result in a diseased liver." Diseased comes from the Old French desaise, "discomfort or sickness," from des-, "without," and aise, "ease."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
In particular, they’re examining how bacteria from diseased gums, and the immune response they trigger, may contribute to conditions including heart disease, diabetes, cognitive decline, arthritis, respiratory disease and chronic liver disease.
From The Wall Street Journal ● Jul. 26, 2026
Wacky animal sidekicks once felt vibrant in a holistic world of artifice; here, a goggle-eyed rooster just looks diseased.
From Los Angeles Times ● Jul. 9, 2026
They found that the same senescent macrophage signature was significantly higher in diseased livers than in healthy ones.
From Science Daily ● Apr. 16, 2026
They evaluated how each substance affected the diseased nerve cells, leading to the identification of sildenafil as a promising candidate.
From Science Daily ● Mar. 31, 2026
Whatever was twisted or diseased in the human soul was present in that room.
From "The Ear, the Eye, and the Arm" by Nancy Farmer
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
