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

Over the next 60 years, polio, measles, rubella, smallpox and other illnesses nearly vanished. — Dr. Marianne Parshley, Hartford Courant, 10 Aug. 2026

The defense said Davis left the narcotics trade in 2009 and worked a steady job before illness forced him to retire in 2014. — CBS News, 10 Aug. 2026

Inter Miami paid tribute to Lionel Messi’s father, Jorge Messi, after his death following an illness was announced on Saturday. — Avi Creditor, New York Times, 9 Aug. 2026

Nelson, demoralized by the trade, missed nine games that season due to illness and resigned under pressure three months later in February 1995. — John Raby, Chicago Tribune, 9 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