sleeper

noun

sleep·​er ˈslē-pər 

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

3

: sleeping car

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

7

: mole entry 2 sense 4

Synonyms

• dozer
• slumberer

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

Share [Findings] Juvenile Japanese eels can escape from the stomachs of dark sleepers by pushing their tails back through the fish’s esophagus and out its gills. —Rafil Kroll-Zaidi, Harper's Magazine, 2 Jan. 2025

Back sleepers may benefit from positioning a pillow beneath their knees to relieve lumbar tension. —Richard Menger Md Mpa, Forbes, 1 Jan. 2025

The Britannic Explorer, the first luxury sleeper train in England and Wales, is next in its very stylish lineup. —Fanny Guénon Des Mesnards, Architectural Digest, 28 Dec. 2024

Where Season 1 thrived on discovery — not only the grand revelation of each new game, including their rules and customs, but also a sleeper hit that caught on by word of mouth rather than pre-release hype — Season 2 survives by knowing there’s less to discover. —Ben Travers, IndieWire, 26 Dec. 2024

Word History

First Known Use

12th century, in the meaning defined at sense 1

Phrases Containing sleeper

• heavy sleeper
• light sleeper
• sleeper cell
• sleeper sofa
• sound sleeper

Kids Definition

sleeper

noun

sleep·​er ˈslē-pər 

1

: one that sleeps

2

: a horizontal beam to support something on or near ground level

3

: sleeping car

4

: someone or something considered unlikely to succeed that suddenly becomes successful