[ slee-per ]
/ ˈsli pər /


Nearby words

  1. sleep-out,
  2. sleep-over,
  3. sleep-terror disorder,
  4. sleep-wake cycle,
  5. sleepcoat,
  6. sleeper seat,
  7. sleeper terrorist,
  8. sleeping,
  9. sleeping bag,
  10. sleeping beauty

Origin of sleeper

Middle English word dating back to 1175–1225; see origin at sleep, -er1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for sleeper

British Dictionary definitions for sleeper


/ (ˈsliːpə) /


Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for sleeper



Old English slæpere "one who sleeps, one who is inclined to sleep much," agent noun from sleep (v.). Meaning "strong horizontal beam" is from c.1600. Meaning "dormant or inoperative thing" is from 1620s. Meaning "railroad sleeping car" is from 1875. Sense of "something whose importance proves to be greater than expected" first attested 1892, originally in American English sports jargon, probably from earlier (1856) gambling slang sense of "unexpected winning card." Meaning "spy, enemy agent, terrorist etc. who remains undercover for a long time before attempting his purpose" first attested 1955, originally in reference to communist agents in the West.

Online Etymology Dictionary, © 2010 Douglas Harper