sleeper

USAGE SUMMARY

The word "sleeper" is correct and usable in written English.
You can use "sleeper" to refer to a person who is sleeping, a train car with sleeping quarters, or even a sleeper hit, which is an unexpected success. Example sentence: "His sleeper hit single made him an overnight sensation."

✓ Grammatically correct

News & Media

Formal & Business

Human-verified examples from authoritative sources

Exact Expressions

60 human-written examples

The government shutdown proved that attempts by the GOP establishment to co-opt the Tea Party as a source of energy just created a network of political sleeper agents.

The Guardian - Opinion

A package including overnight sleeper travel from London to Venice, and Rome to London, train transfers between Venice, Florence and Rome and six nights in three-star hotels with breakfast, would cost from £819.' Laura Johnson from Travel Counsellors: 'For boats, Brittany has some excellent routes, with a great choice of waterways, from wide river estuaries to canals.

The Guardian - Travel

Instead, BJS activated a kind of sleeper network of crime statisticians in almost every state across the country, who harvested data from police departments but also from coroners' offices and other sources.

The Guardian

It features the singles Sing, Thinking Out Loud and Don't, all three of which were hits: Sing became Sheeran's first UK No 1 single and his second US Billboard Hot 100 top 20 hit, Don't peaked at No 8 in the UK and Thinking Out Loud was a sleeper hit, entering the No 1 spot after 19 weeks in the charts.

The Guardian - Music

For the program, the bureau of justice statistics – nested deep within the Department of Justice – activated a kind of sleeper network of criminologists across the country.

The Guardian

The train is the best option and, if you're travelling from the South-East, even better, the sleeper, the Night Riviera.

The Guardian - Travel

An error was inserted at the editing stage into our story on the Paddington to Penzance sleeper in the article below, when it was made to state that 'Britain's only other sleeper [runs] from London to Fort William in Scotland'.

The Guardian - Travel

Amy Coats is a writer by day, sleeper by night.

The Guardian

Britain's only other sleeper, from London to Fort William in Scotland, faces the same fate.

The Guardian - Travel

The film, which won the Bafta for writer Stephen Beresford and producer David Livingstone for outstanding debut by a British writer, director or producer, was a sleeper hit last year making over £4m at the UK box office.

The Guardian - Film

Are you a good sleeper?

The Guardian - Lifestyle

Expert writing Tips

Best practice

Use the phrase "sleeper hit" as a single unit when referring to artistic or commercial products that find success late in their release cycle.

Common error

Writers sometimes mistakenly use "sleeper" as an adjective when they mean "sleepy". Remember that "sleeper" is a noun (the thing or person), while "sleepy" is the adjective describing the state of being tired. For example, write "a sleepy child" rather than "a sleeper child".

Linguistic Context

As a polysemous noun, "sleeper" functions as a subject or object referring to diverse entities: a person in a state of rest, a specialized railway carriage, a dormant spy, or a hidden architectural support. Ludwig data confirms its use in both singular and plural forms to categorize individuals or objects based on their dormant or overnight status.

Expression frequency: Very common

Frequent in

News & Media

85%

Formal & Business

10%

Science

5%

Less common in

Social Media

3%

Wiki

1%

Reference

1%

Ludwig's WRAP-UP

The term "sleeper" is a versatile and highly functional noun in the English language, supported by extensive usage in authoritative news outlets like The Economist. As Ludwig AI suggests, its meaning is heavily dependent on context, shifting seamlessly from describing overnight travel to identifying deep-cover espionage or unexpected commercial successes. Whether you are referring to a "heavy sleeper" or a "sleeper hit", the word maintains a consistent neutral register that is appropriate for both formal journalism and everyday conversation. To write effectively, always ensure that your surrounding sentences provide enough clues to distinguish which of its many definitions you intend to use.

More alternative expressions

Phrases that express similar concepts, ordered by semantic similarity:

sleeping car

Refers specifically to the railroad vehicle designed for overnight travel.

dormant agent

A more formal description for the espionage-related definition of the word.

surprise hit

Equivalent to the entertainment industry's use of the term for unexpected success.

undercover operative

Broader term for a spy that might not necessarily be dormant.

railway tie

The standard American English term for the wooden or concrete support under rails.

overnight train

Describes the service rather than the specific car itself.

slumberer

A more literary or archaic term for a person who is sleeping.

heavy sleeper

Refers to a specific type of person who is difficult to wake.

sleeper cell

A compound noun referring to a group of dormant agents.

modded vehicle

Describes the automotive subculture sense of a car with hidden performance.

FAQs

How to use "sleeper" in a sentence?

You can use it to refer to transportation, such as: "We booked a "sleeping car" on the overnight sleeper to Edinburgh." or to refer to success: "The low-budget film became a surprise sleeper hit."

What is the difference between "sleeper" and "sleepy"?

The word "sleeper" is a noun referring to a person who is sleeping or an object, while "sleepy" is an adjective that describes the feeling of wanting to sleep.

What can I say instead of "sleeper" for a spy?

Depending on the level of formality, you can use alternatives like "undercover agent", "dormant agent", or "mole".

Which is correct, "sleeper" or "railway tie"?

Both are correct but depend on the region; "sleeper" is standard in British English, while "railway tie" is the preferred term in American English.