illness
Americannoun
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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.
Then you can truly enjoy your actual days off and better avoid burnout, something 53% of workers report experiencing, according to a 2026 survey by the National Alliance on Mental Illness.
From MarketWatch • Jun. 30, 2026
EastEnders' writers sought advice from mental health charities Samaritans, Mind and Rethink Mental Illness.
From BBC • May 1, 2026
Illness comes whether you are poor or rich, whether you are good or bad.
From Los Angeles Times • Mar. 4, 2026
Illness is predicted to spread faster, infect more people and put higher-risk groups at greater chance of being seriously ill or hospitalized.
From Salon • Nov. 28, 2025
Illness and death still exist and cannot be hidden.
From "The Lives of a Cell" by Lewis Thomas
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.
