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.
Plants are ruthless in shedding those that are damaged or diseased or that they can no longer maintain, for instance during dry weather.
From The Wall Street Journal ● Oct. 16, 2026
The first starts with terror of the unknown and unseen but culminates in sheer pathos; the latter keeps the reader guessing: Is the creature real or merely the product of a diseased imagination?
From The Wall Street Journal ● Oct. 9, 2026
"Farmers may unknowingly buy diseased plants. The trees may look healthy initially, but after five or seven years they can suddenly die, causing huge financial losses," he says.
From BBC ● Sep. 4, 2026
The researchers then examined a large database containing information about different cell types in young, old and diseased human livers.
From Science Daily ● Sep. 3, 2026
The bodies of only five diseased caterpillars provide enough virus to treat an acre of alfalfa.
From "Silent Spring" by Rachel Carson
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Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
