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

According to Acosta, perceptions also vary between those who prefer to stay out of the issue and those who are hyperconnected, sometimes misinformed, or over-informed, and suffering from high levels of anxiety and insomnia. —Osmary Hernández, CNN Money, 6 Dec. 2025

Oblique rays of sunshine entered through the studio’s glass ceiling and shone on Samy’s ashy skin, on his face ravaged by insomnia. —Literary Hub, 5 Dec. 2025

Our day included brain fog, night sweats, insomnia, frozen shoulder, and rage. —Gillian Telling, PEOPLE, 3 Dec. 2025

Symptoms ranged from insomnia to confusion, electric sensations, muscle cramps, agitation, mood swings and derealisation or an alteration in the person’s perception of the world. —David Cox, NBC news, 30 Nov. 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