illness
Americannoun
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illnesses
plural
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poor health; sickness.
He grew up in an environment known for poverty, illness, and little opportunity for education.
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a specific sickness or disease, or an instance of such.
Please be as accurate as possible in listing your childhood illnesses.
- Synonyms:
- infirmity, affliction, ailment
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Obsolete. wickedness.
noun
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a disease or indisposition; sickness
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a state of ill health
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obsolete wickedness
Usage
What does illness mean? Illness is a state of poor health or sickness, as in I’ve had to miss a lot of work due to illness. The word illness is also commonly used to refer to a disease or instance of sickness. This sense of the word is often used when the type of disease is uncertain or unknown or when someone doesn’t want to specify what it is, as in They said that he is in the hospital with an illness, but they didn’t provide any further details. The word illness is based on the adjective ill, meaning sick. Example: The best way to avoid illness is to thoroughly wash your hands.
Other Word Forms
Noun Inflected Forms
Etymology
Origin of illness
Compare meaning
How does illness compare to similar and commonly confused words? Explore the most common comparisons:
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.
See Examples For:
She also could have been exposed to an illness outside of work.
From The Wall Street Journal ● Oct. 6, 2026
A representative for Flatley said that O'Brien died peacefully at the Beacon Hospital in Dublin after an illness, Irish national broadcaster RTÉ reports.
From BBC ● Oct. 5, 2026
The illness is highly fatal, with average fatality rates approaching 100%.
From Salon ● Oct. 5, 2026
“It is the most pressing emerging illness on the island right now,” Claire Seguin, president of the Martha’s Vineyard Hospital, told me.
From Los Angeles Times ● Oct. 4, 2026
He also survived cerebral malaria, a severe mosquito-borne illness that can cause paralysis, coma, and death.
From "At Last She Stood" by Erin Entrada Kelly
Thursday, cautioning of the risk of heat-related illnesses.
From Los Angeles Times ● Oct. 6, 2026
"Particularly things like viral illnesses, while they're not serious, it's important to get enough rest as well," he added.
From BBC ● Sep. 22, 2026
Another major challenge is that Bundibugyo can initially resemble several far more common illnesses.
From Science Daily ● Sep. 20, 2026
In 1912 the Polish biochemist Casimir Funk proposed that illnesses such as scurvy were caused by the absence of specific chemicals in the diet, launching a race to synthesize vitamins.
From The Wall Street Journal ● Sep. 18, 2026
Before Christianity came to Southern Sudan, people there believed in witches, and they thought that illnesses came from being cursed or bewitched.
From "Lost Boy, Lost Girl" by John Bul Dau
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.
