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

• affection
• ail
• ailment
• bug
• complaint
• complication
• condition
• disease
• disorder
• distemper
• distemperature
• fever
• ill
• infirmity
• malady
• sickness
• trouble

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

With this move, the FDA will limit the vaccine’s availability later this year to older adults and those who may be at risk of severe illness, Reuters reported. —Saleen Martin, USA Today, 23 May 2025

Advertisement Advertisement The group’s report presents four main drivers of chronic childhood illness, laying particular blame on the food children eat and their daily habits. —Alana Semuels, Time, 22 May 2025

Most people recover without treatment, however, in rare circumstances, infection can produce more severe illness and require hospitalization. —Meghan Overdeep, Southern Living, 22 May 2025

Listen to this article 5 min Alan Alda is taking on his illness with a smile. —Stephanie Nolasco, FOXNews.com, 21 May 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