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

Riding a national surge of interest in treatments for menopause, the affiliate also began offering specialized care for women in perimenopause, a period before menopause begins that can bring insomnia and brain fog. — Grant Stringer, Mercury News, 21 July 2026

People who develop racing heartbeats, tremors, anxiety, insomnia, reflux, headaches or reproducible palpitations after drinking coffee should not ignore those symptoms simply because population studies are reassuring. — Robert Glatter, Forbes.com, 21 July 2026

Symptoms can include delusions, hallucinations, extreme depression, insomnia, paranoia and rapid mood swings. — N'dea Yancey-Bragg, USA Today, 20 July 2026

Because of their history of poor sleep, people with insomnia may suffer from anxiety about getting inadequate sleep, which can then increase sleeplessness at night. — Lauren Jarvis-Gibson july 18, Fort Worth Star-Telegram, 18 July 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