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

The top three conditions being treated on the platform are insomnia, anxiety and stress, a mental health trifecta that has surged across Brazil in the wake of COVID-19 and ongoing economic instability. —Javier Hasse, Forbes.com, 3 July 2025

Brittany Winfield's 8-year-old daughter, Czarina, suffers from insomnia, migraines and functional nausea. —Caroline Beck, IndyStar, 2 July 2025

Physical symptoms can include weight changes, tiredness, muscle tension, or insomnia. —Brittany Dube, Health, 17 June 2025

They are used recreationally and by people seeking therapeutic benefits for conditions like anxiety, insomnia and chronic pain. —Eleanor Dearman, Fort Worth Star-Telegram, 11 June 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