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

What mainstream psychiatry views as illness would, according to him, be an understandable response to a dysfunctional society. —Georg Szalai, HollywoodReporter, 12 Nov. 2025

Who is most at risk for severe illness, and what foods are most often linked to outbreaks like this one? —Katia Hetter, CNN Money, 12 Nov. 2025

Consume alcohol in moderation to avoid unnecessary illness. —Carrie Madormo, Verywell Health, 12 Nov. 2025

Safety first is best, but the game plan changes when Meiko finally arrives at the meeting and describes her daughter’s illness, which aligns with the symptoms of the mumps. —Zach Dennis, Charlotte Observer, 12 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