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

Other studies have found that aromatherapy can be a helpful treatment for insomnia, the Mayo Clinic said. — Saman Shafiq, USA Today, 15 Sep. 2026

Biographers and historians have documented that Stewart suffered from severe psychological trauma, which caused digestive issues, insomnia, nightmares, shakes and sweats. — Ashley Hume , Larry Fink, FOXNews.com, 10 Sep. 2026

Immediate reactions during those instances include vomiting, insomnia and nightmares, the lawsuit claims. — Paula Wethington, CBS News, 10 Sep. 2026

Despite being prescribed over a dozen medications, Lindsay’s anxiety, depression and insomnia worsen. — Selena Barrientos, PEOPLE, 4 Sep. 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