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

As a practicing psychiatrist, Lembke routinely prescribes stimulants for ADHD, opioids for pain and benzodiazepines for insomnia and anxiety. — James Cirrone, FOXNews.com, 24 Sep. 2026

Note that if your sleeping woes turn into chronic insomnia, more targeted, long-term solutions might be needed, such as CBT-I (Cognitive Behavioral Therapy for Insomnia) or prescription medication. — Stacia Datskovska, Footwear News, 23 Sep. 2026

His first app was a minimalist white-noise tool for insomnia; his second, a to-do list for forgetful people. — Afra Wang, New Yorker, 23 Sep. 2026

Other studies have found that aromatherapy can be a helpful treatment for insomnia, the Mayo Clinic said. — Saman Shafiq, USA Today, 15 Sep. 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