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

Sue noted that Lindsay reported having insomnia, anxiety, and a lack of appetite in the fall of 2022. — Liam Quinn, PEOPLE, 18 Aug. 2026

The Massachusetts mother asked to change her medications nearly every day, saying the drugs were causing intrusive thoughts, insomnia and numbness, said one of her other providers, Rebecca Jollotta. — Nicki Brown, CNN Money, 17 Aug. 2026

In fact, clinical studies have found that drinking tart cherry juice may improve sleep duration and quality, particularly in older adults and people with insomnia. — Kathleen Ferraro, Verywell Health, 17 Aug. 2026

Patrick Clancy testified that Lindsay Clancy repeatedly sought care from psychiatrists and medical professionals for her worsening insomnia and postpartum depression and anxiety from September 2022 to January 2023. — Melina Khan, USA Today, 17 Aug. 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