sleep·​er | \ ˈslē-pər How to pronounce sleeper (audio) \

Definition of sleeper

1 : one that sleeps
2 : a piece of timber, stone, or steel on or near the ground to support a superstructure, keep railroad rails in place, or receive floor joists : stringpiece
4 : someone or something unpromising or unnoticed that suddenly attains prominence or value the low-budget film became the summer's sleeper
5 : children's pajamas usually with feet usually used in plural
6 chiefly British : a small earring or stud worn to keep the hole of a pierced ear from closing

Synonyms for sleeper


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Examples of sleeper in a Sentence

Sleepers were awakened by the sound of a loud crash. He may turn out to be the sleeper in this year's election. The movie was the summer's sleeper. The movie became the sleeper hit of the summer.
Recent Examples on the Web My NPCs are sleeper cells in the box below my TV, ready to activate a friendship on my command. New York Times, 26 July 2022 The 2010 film Salt, about a CIA spy accused of being a Russian sleeper agent, is a notorious example of the basic motherhood problem. Helen Lewis, The Atlantic, 3 Feb. 2022 On Sunday clearing operations continued in the Ghweran neighborhood around the prison to find Islamic State sleeper cells. Sangar Khaleel,, 30 Jan. 2022 Newroz Ahmed, a senior member of SDF, told reporters Wednesday that about 200 armed militants attacked the prison with car bombs and suicide belts and activated other sleeper cells hiding in residential areas around the prison. NBC News, 26 Jan. 2022 But Syria’s fractured politics and geography have helped some sleeper cells to regroup, experts say. Washington Post, 26 Jan. 2022 Kurdish officials have also said that Islamic State sleeper cells were involved; there are reports the group attacked in other areas to siphon off SDF forces to other places and reduce pressure on the prison siege. Nabih Bulos, Los Angeles Times, 26 Jan. 2022 In recent months, Iraqi security forces and commanders have also warned that ISIS sleeper cells are continuing to stage attacks. Hamdi Alkhshali, CNN, 26 Jan. 2022 But its fighters continued with sleeper cells that have increasingly killed scores of Iraqis and Syrians in past months. Bassem Mroue, ajc, 22 Jan. 2022 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sleeper.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of sleeper

12th century, in the meaning defined at sense 1

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The first known use of sleeper was in the 12th century

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Dictionary Entries Near sleeper

sleep disorder


sleeper cell

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Statistics for sleeper

Last Updated

15 Aug 2022

Cite this Entry

“Sleeper.” Dictionary, Merriam-Webster, Accessed 19 Aug. 2022.

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More Definitions for sleeper


sleep·​er | \ ˈslē-pər How to pronounce sleeper (audio) \

Kids Definition of sleeper

1 : someone that sleeps I'm a light sleeper.
2 : a railroad car with berths for sleeping

More from Merriam-Webster on sleeper

Nglish: Translation of sleeper for Spanish Speakers Encyclopedia article about sleeper


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