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

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

But studies targeting transitions both into and out of sleep are starting to unravel the neurobiological underpinnings of these in-between states, yielding an understanding that could explain how sleep disorders, such as insomnia or sleep paralysis, can result when things go awry. —Yasemin Saplakoglu, Quanta Magazine, 17 Oct. 2025

For example, in 1992, the FDA approved Ambien (zolpidem), a drug used to treat insomnia. —Harsh Gupta, Time, 16 Oct. 2025

The data showed that 14 percent of those with chronic insomnia developed mild cognitive impairment or dementia while 10 percent of those who did not have chronic insomnia did. —The Washington Post, San Diego Union-Tribune, 14 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