sleepless

American  

[sleep-lis] / ˈslip lɪs /

adjective

1. without sleep.

   a sleepless night.

2. watchful; alert.

   sleepless devotion to duty.

3. always active.

   the sleepless ocean.

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sleepless British  

/ ˈsliːplɪs /

adjective

1. without sleep or rest

   a sleepless journey

2. unable to sleep

3. always watchful or alert

4. poetic always active or moving

   the sleepless tides

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Other Word Forms

• sleeplessly
  adverb
• sleeplessness
  noun

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

I lay mummy-style and wide-eyed next to him through the sleepless night.

From Los Angeles Times • May 8, 2026

"I will now be busy throughout the day," the visibly tired driver told AFP, his eyes red and heavy after the sleepless night.

From Barron's • Apr. 21, 2026

She believes their problems conceiving naturally were caused, or at least exacerbated, by the war: "all the stress and sleepless nights," Katerina says.

From BBC • Feb. 16, 2026

They simply show that a disciplined, diversified approach offers something rare in investing: higher odds of success with fewer sleepless nights.

From MarketWatch • Feb. 5, 2026

For the better part of an hour, Chronicler lay sleepless in his sweet-smelling bed, rolling restlessly from side to side.

From "The Name of the Wind" by Patrick Rothfuss

Related Words

• fidgety