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

Just make sure the encasement is flexible enough to stretch as your body sinks into the bed, which is especially important for side sleepers. —Kristi Kellogg, Architectural Digest, 31 Mar. 2025

Beckham Hotel Collection Queen Bed Pillows, $36 with coupon $80 $36 at Amazon Designed to support all types of sleepers — stomach, back, and side — the pillows have plush down alternative filling and are encased in cotton covers that are breathable. —Isabel Garcia, People.com, 28 Mar. 2025

By the Core 4 Decluttering Method Hotel Surplus The outlet is donating and offering discounts on a wide array of new furniture, from sleeper sofas to rolling cots, for those in need. —Bryce Jones, Better Homes & Gardens, 23 Mar. 2025

If healthy, Baylor is a sneaky sleeper pick to make it through the second weekend of play. —Michael Waterloo, The Athletic, 16 Mar. 2025

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

Rhymes for sleeper

• beeper
• cheaper
• creeper
• deeper
• keeper
• reaper
• steeper
• sweeper
• beekeeper
• bookkeeper
• doorkeeper
• gamekeeper

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