insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged and usually abnormal inability to get enough sleep especially due to trouble falling asleep or staying asleep

chronic insomnia

Insomnia is a patient-reported problem characterized by difficulty falling asleep or difficulty maintaining sleep; ie, frequent awakenings, difficulty returning to sleep after awakenings, or awakening too early with inability to return to sleep.

—Daniel J. Buysse

Synonyms

• restlessness
• wakefulness
• sleeplessness
• alertness

Examples of insomnia in a Sentence

has suffered from insomnia virtually his entire life

Recent Examples on the Web

Sedentary lifestyles are linked to a higher risk of insomnia, mortality and cardiovascular disease. —Gina Park, CNN Money, 27 Oct. 2025

For someone with sleep-onset insomnia, Kat says, lights-out might have come earlier, and the scheme would have been different. —Rowan Jacobsen, Harpers Magazine, 24 Oct. 2025

The lawsuit said many of the plaintiffs experienced debilitating panic attacks and insomnia, among other physical ailments. —Christina Hall, Freep.com, 23 Oct. 2025

Meanwhile, summer-pattern SAD is often linked with a poor appetite and insomnia. —Maggie O'Neill, SELF, 20 Oct. 2025

Word History

Etymology

Latin, from insomnis sleepless, from in- + somnus sleep — more at somnolent

First Known Use

1739, in the meaning defined above

Kids Definition

insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged inability to sleep

Medical Definition

insomnia

noun

in·​som·​nia in-ˈsäm-nē-ə 

: prolonged and usually abnormal inability to obtain adequate sleep especially due to difficulty falling asleep or staying asleep

called also agrypnia