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

No illnesses or allergic reactions have been reported to date. —Adeola Adeosun, MSNBC Newsweek, 15 June 2025

For the past several years, the poet laureate of Colorado has confronted a life-threatening illness after their diagnosis with stage 4 ovarian cancer. —Matthew Carey, Deadline, 15 June 2025

Writer Kim Davis lost 10 years of her life to illness, injury and personal tragedies, which spurred her to seize the moment and set off to travel the world for a year. —Maureen O'Hare, CNN Money, 14 June 2025

Accident and illness policies from Figo are affordable with generous limits. —Liz Knueven, CNBC, 13 June 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