# sleeper

> English word · Noun · IPA /ˈsliːpə(ɹ)/ · frequency rank #15,911

## Definitions
1. Someone who sleeps.
2. That which lies dormant, as a law.
3. A spy, saboteur, or terrorist who lives unobtrusively in a community until activated by a prearranged signal; may be part of a sleeper cell.
4. A small starter earring, worn to prevent a piercing from closing.
5. A railway sleeping car.
6. A sleeper hold.
7. Something that achieves unexpected success after an interval of time.
8. Any of family Odontobutidae of goby-like bottom-feeding freshwater fish.
9. A nurse shark (family Ginglymostomatidae).
10. A type of pajama for a person, especially a child, that covers the whole body, including the feet.
11. An automobile which has been internally modified to excess, while retaining a mostly stock appearance in order to fool opponents in a drag race, or to avoid the attention of the police.
12. A sedative.
13. A bet placed on the gambling table and then forgotten about by the gambler.
14. A pod or similar device containing a person in cryosleep.

## Etymology
From Middle English sleper, equivalent to sleep + -er.

## Easily confused with
- **sleeve** (https://plainspell.com/en/vs/sleeper-vs-sleeve)
- **sleeps** (https://plainspell.com/en/vs/sleeper-vs-sleeps)
- **sleepy** (https://plainspell.com/en/vs/sleeper-vs-sleepy)
- **sleeves** (https://plainspell.com/en/vs/sleeper-vs-sleeves)
- **slender** (https://plainspell.com/en/vs/sleeper-vs-slender)
- **slipper** (https://plainspell.com/en/vs/sleeper-vs-slipper)
- **sleeved** (https://plainspell.com/en/vs/sleeper-vs-sleeved)
- **steeper** (https://plainspell.com/en/vs/sleeper-vs-steeper)
- **sweeper** (https://plainspell.com/en/vs/sleeper-vs-sweeper)
- **sleepover** (https://plainspell.com/en/vs/sleeper-vs-sleepover)
- **sleep** (https://plainspell.com/en/vs/sleep-vs-sleeper)
- **seeker** (https://plainspell.com/en/vs/seeker-vs-sleeper)

## Common misspellings (10)
`lseeper`, `seleper`, `sleeepr`, `sleeperr`, `sleepper`, `sleepre`, `slepeer`, `sleper`, `slleeper`, `ssleeper`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/sleeper