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

Nick’s panic evolves into a crippling insomnia that leaves him on the edge of psychosis. —Emily Witt, New Yorker, 13 Aug. 2025

Fourteen bacterial taxa were found to increase insomnia risk, while eight looked to shield us from poor sleep. —New Atlas, 12 Aug. 2025

Their analysis revealed associations between specific gut microbes and insomnia. —Hannah Millington, MSNBC Newsweek, 12 Aug. 2025

What is Ambien? Ambien, also known by its generic name, zolpidem, is a prescription medication used to treat insomnia by helping individuals fall asleep quicker and stay asleep. —Charles Trepany, USA Today, 22 July 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