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

The lack of regulations placed on these toxic supplements leads many teens to use these products with no idea of the risks, resulting in insomnia, contributing to depression and mood swings, and straining the liver and kidneys, which could lead to further damage. —Jad Abdel Nour, Hartford Courant, 4 May 2026

The immediate aftermath of a split tends to be less clear, a hazy maelstrom that can involve medicinal tubs of ice cream, insomnia by way of intrusive thoughts, and an aversion to wearing anything other than sweats. —Paula Mejía, The Atlantic, 3 May 2026

Others may be dealing with insomnia, which could require additional interventions, Rowley says. —Pien Huang, NPR, 2 May 2026

Despite his busy schedule, the singer reportedly still struggled with insomnia. —Alex Gurley, PEOPLE, 28 Apr. 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