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 of insomnia

• restlessness
• wakefulness
• sleeplessness
• alertness

Examples of insomnia in a Sentence

has suffered from insomnia virtually his entire life

Recent Examples on the Web

Still, they are promoted for a range of medical uses, including insomnia, anxiety, inflammatory conditions and migraines. — Arkansas Online, 29 Oct. 2026

This can lead to symptoms like insomnia, muscular tension, and rumination that can hurt your health. — Juli Fraga, Time, 29 Oct. 2026

Sleep apnea, restless legs syndrome and chronic insomnia may require targeted treatment. — Emily Cegielski, Flow Space, 28 Oct. 2026

Hyperarousal of the brain can contribute to insomnia, LaValle added. — Angelica Stabile, FOXNews.com, 27 Oct. 2026

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