sleeper

American  

[slee-per] / ˈsli pər /

noun

• sleepers
  plural

1. a person or thing that sleeps.

2. a heavy horizontal timber for distributing loads.

3. Building Trades.

   1. any long wooden, metal, or stone piece lying horizontally as a sill or footing.

   2. any of a number of wooden pieces, laid upon the ground or upon masonry or concrete, to which floorboards are nailed.

4. a sleeping car.

5. Informal. something or someone that becomes unexpectedly successful or important after a period of being unnoticed, ignored, or considered unpromising or a failure.

   The play was the sleeper of the season.

6. merchandise that is not quickly sold because its value is not immediately recognized.

7. Often sleepers. one-piece or two-piece pajamas with feet, especially for children.

8. bunting.

9. a sofa, chair, or other piece of furniture that is designed to open up or unfold into a bed; convertible.

10. Also called sleep, sand. a globule that forms at the inner corner of the eye, especially during sleep, from the accumulated secretion of the glands of the eyelid.

11. any of several gobioid fishes of the family Eleotridae, of tropical seas, most species of which have the habit of resting quietly on the bottom.

12. Slang. a spy; mole.

13. Slang. a juvenile delinquent sentenced to serve more than nine months.

14. Bowling. a pin that is hidden from view by another pin.

15. Chiefly British. a timber or beam laid in a railroad track, serving as a foundation or support for the rails; tie.

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sleeper British  

/ ˈsliːpə /

noun

1. a person, animal, or thing that sleeps

2. a railway sleeping car or compartment

3. US and Canadian equivalent: tie. one of the blocks supporting the rails on a railway track

4. a heavy timber beam, esp one that is laid horizontally on the ground

5. a small plain gold circle worn in a pierced ear lobe to prevent the hole from closing up

6. a wrestling hold in which a wrestler presses the sides of his opponent's neck, causing him to pass out

7. an unbranded calf

8. Also called: sleeper goby. any gobioid fish of the family Eleotridae, of brackish or fresh tropical waters, resembling the gobies but lacking a ventral sucker

9. informal a person or thing that achieves unexpected success after an initial period of obscurity

10. a spy planted in advance for future use, but not currently active

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Other Word Forms

Noun Inflected Forms

• sleepers
  plural

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Etymology

Origin of sleeper

Middle English word dating back to 1175–1225; see origin at sleep, -er ¹

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Explanation

A sleeper is something that succeeds when no one thought it would. That low-tech movie about shark attacks that you shot on vacation and edited in your basement? It could be a sleeper if you market it in the right way. You probably know that sleeper can be used in an obvious sense to refer to someone who is asleep. But you also may hear the word used to describe something that becomes an unexpected success, like "a sleeper of a film" featuring unknown actors that ends up becoming the big summer hit. This sense of the word may have originated in the world of gambling in the nineteenth century. When a card player unexpectedly drew a winning card, the card was called "a sleeper."

Example Sentences

See Examples For:

sleeper sleepers

“It’s kind of like traveling overnight in a sleeper car on a train,” says Yulia.

From The Wall Street Journal ● Oct. 4, 2026

But they can change shape during the night, particularly if the sleeper moves around a lot and the pillow can end up bunched towards the headboard.

From BBC ● Sep. 27, 2026

Thompson, a rookie who ran the fastest 40-yard dash in the NFL scouting combine, has impressed with his speed and could be a sleeper contributor in space.

From Los Angeles Times ● Sep. 7, 2026

If you’re in the mood for a thriller: Hulu’s sleeper hit Furious—which just wrapped up its first season—stars a trio of knockout performances, but one of its stars towers above the rest.

From Slate ● Aug. 31, 2026

Two sleeper agents from communist Czechoslovakia had been living for nearly a decade in the United States, posing as defectors and staunch anticommunists.

From "Spies: The Secret Showdown Between America and Russia" by Marc Favreau

In diligent, exhausted Japan, self-described elite "competitive sleepers" vied to lie down, relax and nap the fastest and deepest in a contest organised by a mattress company.

From Barron's ● Oct. 6, 2026

For back sleepers, some manufacturers advertise a pillow with a dip in the middle that is raised at the sides.

From BBC ● Sep. 27, 2026

Patel called the Nature paper “an important study” because the participants were actively experiencing medical conditions that can affect sleep, such as insomnia, and said “we need more” research on how wearables affect irregular sleepers.

From The Wall Street Journal ● Sep. 6, 2026

"Our study suggests there may be different biological pathways between long and short sleepers that lead to the same outcome, late-life depression, and we shouldn't treat them the same way."

From Science Daily ● Aug. 24, 2026

We sat on a bench among the sleepers.

From "Native Speaker" by Chang-rae Lee

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