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

On Friday, the pope strongly reiterated the Church's pro-life teachings, criticizing initiatives to allow assisted dying for those who have incurable illnesses. — Joshua McElwee, Arkansas Online, 26 Sep. 2026

Hair loss in women can be caused by many things, including your genetics, illnesses, nutritional deficiencies, physiological stress and shifts in hormones. — Lindsey Bever, Washington Post, 26 Sep. 2026

These dangerous illnesses are all completely preventable and serve as a reminder of the importance of proper vaccines to protect the health of our families and children. — Chicago Tribune, 26 Sep. 2026

Pope Leo’s visit, however, comes after France’s recent national debate and subsequent passage of legislation allowing adults with incurable illnesses to receive lethal medication. — Tyler Speicher , Courtney Walsh, FOXNews.com, 25 Sep. 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