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

At the top end of the market, England and Wales’ first luxury sleeper train, ​​The Britannic Explorer, A Belmond Train, UK, will hit the rails in July 2025. —Maureen O'Hare, CNN, 7 Dec. 2024

If someone on your shopping list tends to be a hot sleeper, these pajamas can help. —Toni Sutton, People.com, 6 Dec. 2024

Hosting overnight guests looks much more chic with a trundle sleeper like this one. —Nashia Baker, Architectural Digest, 2 Dec. 2024

Unlike ordinary memory foam, the design and fabric was originally created by NASA to cushion pilots during test flights and later perfected by the Tempur-Pedic team to appeal to all sorts of sleepers. —Paris Wilson, Condé Nast Traveler, 2 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