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

In tracking a potential illness in the locker room, wide receiver Jonathan Mingo popped up on the injury report on Wednesday with an illness and was listed as questionable. — Nick Harris, Fort Worth Star-Telegram, 9 Oct. 2026

What illness, which the institute studies, has been the subject of speculation about her death? — New York Times, 9 Oct. 2026

The illness is characterized by muscle rigidity in the torso, arms and legs. — Andrea Flores, Los Angeles Times, 9 Oct. 2026

Larsson was still dealing with the lingering effects of an illness that has also forced him to miss practice this week. — Anthony Chiang, Miami Herald, 9 Oct. 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