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:
Hoetzlein had a history of severe mental illness, the statement said.
From Los Angeles Times ● Aug. 17, 2026
The results show that dormant viruses can reactivate frequently in people who appear to have functioning immune systems during severe illness, particularly when systemic inflammation is elevated.
From Science Daily ● Aug. 16, 2026
EU officials have agreed to study an experimental vaccine against Lyme disease, the world's most common tick-borne illness, its developers said Friday.
From Barron's ● Aug. 14, 2026
Messi's father Jorge was 68 when he died last week following a long illness.
From BBC ● Aug. 12, 2026
Some people were only lightly affected; some were stricken with all the savage force of the illness.
From "A Girl Named Disaster" by Nancy Farmer
It added it was not aware of any specific illnesses linked to its products.
From Barron's ● Aug. 14, 2026
The United States spends much more on actual medical care, Cohen said, in terms of curing illnesses — but much less on preventative care.
From Salon ● Aug. 11, 2026
The company said it was not aware of any illnesses linked to the products but that it was withdrawing them across 26 US states.
From BBC ● Aug. 10, 2026
Taylor said it wasn’t aware of any reported illnesses linked to its products containing the jalapeños.
From The Wall Street Journal ● Aug. 10, 2026
She worried about Charles’s and the children’s illnesses.
From "Charles and Emma: The Darwins' Leap of Faith" by Deborah Heiligman
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.
