sleepless
Americanadjective
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without sleep.
a sleepless night.
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watchful; alert.
sleepless devotion to duty.
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always active.
the sleepless ocean.
adjective
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without sleep or rest
a sleepless journey
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unable to sleep
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always watchful or alert
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poetic always active or moving
the sleepless tides
Other Word Forms
Etymology
Origin of sleepless
late Middle English word dating back to 1375–1425; see origin at sleep, -less
Explanation
If something is sleepless, it's wakeful or restless, like a sleepless night spent in an unfamiliar house listening to spooky noises. You might be sleepless the night before an exciting trip, or sleepless in your sleeping bag because the ground feels cold and hard beneath you. Whenever sleep won't come—because of worry, excitement, or discomfort—you can describe yourself (and the night) as sleepless. It's used in a literary way as well, to mean "restless" or "constantly moving," like a sleepless willow tree swaying in the breeze.
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Polly Turton, head of climate action at NGO Shade the UK, said the situation was "the new normal. The sleepless nights we're all experiencing, we are going to have to adapt to," she said.
From Barron's • Jun. 26, 2026
New dads face psychological pressures, from sleepless nights to sky-high bills, which can contribute to postpartum depression.
From Los Angeles Times • Jun. 10, 2026
For the better part of a year, I spent myriad sleepless nights wrestling with my conscience.
From Salon • Jun. 8, 2026
Some policyholders died while awaiting their funds, while others wrote in victim-impact statements of sleepless nights, depression and inability to pay medical bills.
From The Wall Street Journal • May 26, 2026
Seven months of sleepless nights and peering over my shoulder and trying to act normal.
From "An Ember in the Ashes" by Sabaa Tahir
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
