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

According to the Thunder, Gilgeous-Alexander is dealing with an illness, which has put his status as questionable. —Justin Grasso, MSNBC Newsweek, 27 Nov. 2025

Laboratory tests of 36 samples of formula from three different lots showed that five samples contained the type of bacteria that can lead to the rare and potentially deadly illness, the company said Monday on its website. —Arkansas Online, 26 Nov. 2025

As families discover The Little Holiday Munchkin this season, each book purchased helps support the Dunkin’ Joy in Childhood Foundation, which funds joyful experiences for kids battling hunger or illness. —Moná Thomas, PEOPLE, 26 Nov. 2025

The Bard was likely occupied in London and received word only days after Hamnet’s illness ravaged him. —Nathan Smith, Time, 26 Nov. 2025

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