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

What starts as a seemingly minor disturbance spirals into something far more sinister — triggering migraines, nosebleeds and insomnia. —Monica Mercuri, Forbes.com, 1 June 2026

Yoga may significantly reduce the insomnia, fatigue and mood disturbances many survivors endure after remission, a recent clinical trial found. —Teresa Mull, FOXNews.com, 30 May 2026

Not getting enough magnesium is linked with insomnia and lower sleep quality, Susie adds. —Sarah Klein, Time, 28 May 2026

The student also showed a lack of motor functioning, uncontrolled emotions and developed a form of insomnia that prevented a regular sleep schedule. —Jt Moodee Lockman, CBS News, 27 May 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