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

• restlessness
• wakefulness
• sleeplessness
• alertness

Examples of insomnia in a Sentence

has suffered from insomnia virtually his entire life

Recent Examples on the Web

Herbsnleaf sells edibles, vapes, drinks, capsules and oils, all designed to deliver the benefits of CBD in treating chronic pain, anxiety and insomnia. —Shawn Price, Oc Register, 19 Sep. 2025

The programme has also been designed to educate guests on how to achieve good sleep when back at home and how factors, such as nutrition, gut health, stress and water retention, are all interconnected and play a part with insomnia and wakefulness. —Angelina Villa-Clarke, Forbes.com, 19 Sep. 2025

Science will eventually catch all of these wounds – PTSD, insomnia, traumatic brain injuries. —Katie Atkinson, Billboard, 19 Sep. 2025

Over the course of the study, 14% of the people with chronic insomnia developed mild cognitive impairment or dementia, compared to 10% of those who did not have the sleep disorder. —Melissa Rudy, FOXNews.com, 18 Sep. 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