illness

noun

ill·​ness ˈil-nəs 

1

a

: sickness sense 2

b

: an unhealthy condition of body or mind

2

obsolete

a

: wickedness

b

: unpleasantness

Synonyms of illness

• disease
• ailment
• ill
• sickness
• fever

Examples of illness in a Sentence

Her body was not able to defend itself against illness.

Hundreds of soldiers died from illness and hunger.

He showed no signs of illness.

Scientists have not yet found a cure for this illness.

cancer, diabetes, and other illnesses

She died at the age of 60 after a brief illness.

Recent Examples on the Web

Fabares died Saturday in Los Angeles after a brief illness, her family announced. — Cheryl Cheng, HollywoodReporter, 23 Aug. 2026

Later, a fellow resident gave him a house, and neighbors supported him, especially during his final two years of illness. — Laura Sharman, CNN Money, 22 Aug. 2026

Those memories of Keegan chasing, Keegan scoring, Keegan leading 1970s Liverpool across England and Europe to trophy upon trophy were clattered by 2026 reports of his illness and death. — Michael Walker, New York Times, 22 Aug. 2026

Many of the chihuahuas are emaciated and have varying illnesses, fleas and other medical concerns, according to Humane Indiana staff. — Anna Ortiz, Chicago Tribune, 22 Aug. 2026

Word History

First Known Use

circa 1500, in the meaning defined at sense 2a

Phrases Containing illness

• bipolar illness
• illness anxiety disorder
• manic-depressive illness
• mental illness

Rhymes for illness

• stillness

Kids Definition

illness

noun

ill·​ness ˈil-nəs 

1

: an unhealthy condition of body or mind

2

: sickness sense 2

Medical Definition

illness

noun

ill·​ness ˈil-nəs 

: an unhealthy condition of body or mind : sickness