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

At the time, Monroe was under the constant care of a doctor and psychiatrist, who had prescribed her numerous medications to treat mental health issues as well as her insomnia. —Angela Andaloro, PEOPLE, 4 Sep. 2025

Ashwagandha may also be effective in easing stress and insomnia, according to the National Center for Complementary and Integrative Health. —Jocelyn Solis-Moreira, Flow Space, 3 Sep. 2025

And while doctors know stopping SSRIs can sometimes cause unpleasant side effects like dizziness, anxiety, insomnia and nausea, some people described symptoms that went further – that lasted months, even years. —Emily Kwong, NPR, 2 Sep. 2025

Its users can also experience anorexia, insomnia, seizures and hallucinations. —Michael Slaten, Oc Register, 29 Aug. 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