sleeper

noun
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

Synonyms

Visit the Thesaurus for More 

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, BostonGlobe.com, 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

Buying Guide

Our Reviews team has selected the best weighted blankets.

Learn More About sleeper

Time Traveler for sleeper

Time Traveler

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

See more words from the same century

Dictionary Entries Near sleeper

sleep disorder

sleeper

sleeper cell

See More Nearby Entries 

Statistics for sleeper

Last Updated

15 Aug 2022

Cite this Entry

“Sleeper.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sleeper. Accessed 19 Aug. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for sleeper

sleeper

noun
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

Britannica.com: Encyclopedia article about sleeper

WORD OF THE DAY

Test Your Vocabulary

Challenging Words You Should Know

  • hedgehog reading a book
  • Often used to describe “the march of time,” what does inexorable mean?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Universal Daily Crossword

A daily challenge for crossword fanatics.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!