sickness

noun

sick·​ness ˈsik-nəs 

1

a

: ill health : illness

b

: a disordered, weakened, or unsound condition

2

: a specific disease

3

: nausea, queasiness

Synonyms of sickness

• illness

Examples of sickness in a Sentence

He died from an unknown sickness.

she was plagued by sickness most of her adult life

Recent Examples on the Web

According to Netflix’s synopsis, Nancy and Robin discover a sickness spreading through town, a mysterious man tailing their movements, and a series of clues that suggest something more dangerous than mere supernatural echoes. —Melissa Fleur Afshar, MSNBC Newsweek, 4 Dec. 2025

But the number of kids who need to be airlifted to the pediatric hospital due to a life-threatening sickness or condition has been increasing over the past few years, according to Kelly Besl, a nurse who serves as the clinical director of Cincinnati Children’s critical care transport team. —Elizabeth B. Kim, Cincinnati Enquirer, 3 Dec. 2025

This can lead to extreme sickness, weakness, and even paralysis. —Kait Hanson, Southern Living, 30 Nov. 2025

Ruling out sickness or potential allergies as other contributing factors is also important. —Daryl Austin, USA Today, 28 Nov. 2025

Word History

First Known Use

before the 12th century, in the meaning defined at sense 1a

Phrases Containing sickness

• acute mountain sickness
• African sleeping sickness
• altitude sickness
• decompression sickness
• milk sickness
• morning sickness
• motion sickness
• mountain sickness
• radiation sickness
• serum sickness
• sickness benefit
• sleeping sickness
• travel sickness

Rhymes for sickness

• quickness
• thickness
• homesickness
• seasickness

Kids Definition

sickness

noun

sick·​ness ˈsik-nəs 

1

: ill health : illness

2

: a specific disease : malady

3

: nausea sense 1

Medical Definition

sickness

noun

sick·​ness ˈsik-nəs 

1

: the condition of being ill : ill health

2

: a specific disease

3

: nausea