a person who has or experiences insomnia, the inability, especially when chronic, to obtain sufficient sleep, through difficulty in falling or staying asleep: Her husband, an insomniac, had at last fallen asleep at the computer, head resting on the keyboard.
Once you know the Latin root somn-, which you now do, then you will also recognize it in some related words— somnolent, meaning “sleepy, drowsy,” somniferous, meaning “sleep-inducing,” and somnambulate, meaning “to sleepwalk.”
By now, you can probably guess that a somnambulist is a sleepwalker. Perhaps the most famous somnambulist is Cesare, a carnival attraction in the 1920 silent film The Cabinet of Doctor Caligari.
We hope this story hasn’t been too somniferous—but, if it has, pleasant dreams!
— Insomniac: An album by the punk band Green Day, released in 1995.
— Insomniac with Dave Attell: A Comedy Central television show, hosted by Dave Attell, which ran in the early 2000s.
- an·ti-in·som·ni·ac, adjective, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use insomniac in a sentence
On dreary winter days, it flickers like a flame in the corner of the room, and on insomniac nights, when the rest of the world is asleep, it stays up with me, troubling the water.My doctor told me to get a dog, but I couldn’t. Meet my emotional support fish. | Will Dowd | October 7, 2021 | Washington Post
I became an insomniac, avoiding sleep at all costs, to keep the clawing terror at bay.My Personal Quest to Study Supernovae on Mars - Issue 104: Harmony | Sarafina El-Badry Nance | September 1, 2021 | Nautilus
By writing about my wild sleeps, I could bring my fellow insomniacs with me.A Sleep Storyteller Reveals Her Secrets for Drifting Off Naturally | Phoebe Smith | August 6, 2020 | Time
Most people are insomniac, mainly because they are overanxious about their sleep.Psychotherapy | James J. Walsh
Telling a careworn insomniac not to worry is as silly and useless as telling a lovelorn person to stop being in love.Psychoanalysis | Andr Tridon
Consciousness came back in little dribbles like a montage—half reality and half nightmare of the insomniac.A Woman's Place | Mark Irvin Clifton
British Dictionary definitions for insomniac
exhibiting or causing insomnia
a person experiencing insomnia
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012