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

But in the past two years, large outbreaks have hit multiple states, spawning thousands of illnesses, including about a dozen deaths. — ABC News, 13 Nov. 2026

The outbreak was first detected in Mongbwalu, a gold-mining town of around 130,000 people in Ituri province in northeastern Congo, after the WHO was alerted on May 5 about an unusual cluster of illness and deaths. — Anthony W. Gambino, Time, 13 Nov. 2026

His characters’ anxieties about illness and mortality reflect his own, and Almodóvar’s latest is similarly interested in notions of legacy and decline. — Los Angeles Times, 13 Nov. 2026

Larsson, who was slowed by an illness in preseason, replaced Andrew Wiggins in the starting lineup last Sunday against Sacramento, and the Heat has won each of his two starts. — Barry Jackson, Miami Herald, 13 Nov. 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