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

The hip-hop musician died on Monday, April 6, in Atlanta following a brief illness, her family told Billboard in a statement announcing the news. —Jack Irvin, PEOPLE, 10 Apr. 2026

Finally, smoking deaths may seem to be unremarkable because some of the illnesses that cigarette smoking causes, such as heart disease or cancer, are commonplace. —Marie Helweg-Larsen, The Conversation, 10 Apr. 2026

Taveras was in the starting lineup after Tyler O’Neill was scratched with an illness. —ABC News, 10 Apr. 2026

The Raptors were missing Chucky Hepburn (right knee surgery recovery) and Trayce Jackson-Davis (illness). —Anthony Chiang, Miami Herald, 10 Apr. 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