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

That work would build on other efforts that have shown that tweaking the gut microbiome could, among other things, fight multiple sclerosis, improve the effectiveness of cancer immunotherapy treatment, and potentially combat insomnia. —New Atlas, 14 Nov. 2025

Cost of insomnia Americans clearly needed help getting a good night’s rest. —Katherine Laidlaw, HubSpot, 14 Nov. 2025

Often, this process is accompanied by a wide range of symptoms, including hot flashes and night sweats as well as mood swings, joint pain, vaginal dryness, insomnia, and memory problems. —Emily Kay Votruba, EverydayHealth.com, 11 Nov. 2025

Anyone who relies on melatonin nightly should consider seeing a sleep specialist to determine potential underlying issues like chronic insomnia or stress, Okwuosa said. —Stephanie Brown, Verywell Health, 10 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