Definition

1. Noun:
   • A person who is asleep: Someone who is in a state of sleep.
   • A railroad tie: A rectangular support, typically made of wood or concrete, laid crosswise under and supporting the rails on a railway track.
   • A sleeping car: A railway passenger car equipped with berths or beds for overnight travel.
   • An unexpected success: A person or thing that achieves unexpected success or popularity, often after an initially quiet or unnoticed period.
   • A spy or agent: A person who lives unobtrusively in a foreign country, often for a long period, before being activated for espionage or sabotage.
   • A type of pajama: A one-piece garment for sleeping, especially for children, that covers the feet.
   • A type of fish: A bottom-dwelling marine fish that remains still on the seafloor.
   • A piece of furniture: A sofa or couch that can be converted into a bed.

Usage Examples

• Noun:
  • He is a heavy sleeper and didn't hear the alarm. (Referring to a person who sleeps deeply.)
  • Workers replaced the rotten wooden sleeper on the track. (Referring to a railroad tie.)
  • We booked a compartment in the sleeper for the overnight journey. (Referring to a sleeping car.)
  • That low-budget film was the summer's biggest sleeper. (Referring to an unexpected hit.)
  • The agency had a sleeper living in the capital for a decade. (Referring to a dormant spy.)
  • The toddler wore warm sleepers on cold nights. (Referring to footed pajamas.)
  • We saw a sleeper resting on the sandy bottom while snorkeling. (Referring to the fish.)
  • The small apartment has a sleeper sofa for guests. (Referring to a convertible bed.)

Advanced Usage

• "Sleeper hit": A film, song, or other product that becomes a surprise success.

  • The indie game became a sleeper hit, selling millions of copies.

• "Sleeper cell": A covert group of spies or terrorists who remain inactive until given orders.

  • Intelligence agencies worked to dismantle the sleeper cell.

• "Sleeper effect": A phenomenon where a persuasive message has a delayed impact, becoming more effective over time.

  • The advertisement had a sleeper effect, influencing opinions weeks later.

Variants and Related Words

• Sleep (verb/noun): The state or act of resting naturally with suspended consciousness.
• Sleepy (adjective): Needing or ready for sleep; drowsy.
• Sleeping (adjective/noun): The condition of being asleep.
• Sleepover (noun): A party where guests stay overnight at a friend's house.

Synonyms

• Dark horse: A competitor about whom little is known but who unexpectedly wins or succeeds.
• Berth: A bunk or bed on a ship, train, or other vehicle.
• Crosstie: Another term for a railroad sleeper or tie.
• Mole: A spy who infiltrates an organization and establishes a long-term position.

Related Phrases (Phrasal Verbs)

(Note: "Sleeper" is primarily a noun. Common phrasal verbs are formed with its root, "sleep.") - Sleep in: To sleep later than usual in the morning. - I like to sleep in on weekends. - Sleep over: To stay overnight at someone else's house. - The children are going to sleep over at their cousin's.

Related Idioms

• A sleeper must be awakened: An idiom suggesting that a person with potential must be roused to action or awareness.
  • He has so much talent, but he's like a sleeper who must be awakened.
• To buy a sleeper: To purchase something (often a stock or antique) that is undervalued and later increases in worth.
  • He bought the painting for a small sum; it was a real sleeper and is now very valuable.

Noun

1. an unexpected hit
   • that movie was the sleeper of the summer
2. tropical fish that resembles a goby and rests quietly on the bottom in shallow water
3. a piece of furniture that can be opened up into a bed
4. pajamas with feet; worn by children
5. a passenger car that has berths for sleeping
6. one of the cross braces that support the rails on a railway track
   • the British call a railroad tie a sleeper
7. an unexpected achiever of success
   • the winner was a true sleeper--no one expected him to get it
8. a spy or saboteur or terrorist planted in an enemy country who lives there as a law-abiding citizen until activated by a prearranged signal
9. a rester who is sleeping