noun Someone who is sleeping.
- The sleeper on the couch did not move when we turned on the lights.
- I am a deep sleeper, so my alarm clock rarely wakes me.
- She's a light sleeper — the slightest noise wakes her up.
noun A spy or agent who lives an ordinary life in a community until activated for a mission.
- The novel reveals that their friendly neighbor was a sleeper planted there years ago.
- Police believed the quiet shopkeeper was a sleeper waiting for orders from abroad.
- The film follows a Cold War sleeper waiting years for a single coded message.
noun Something — a film, product, or competitor — that unexpectedly becomes a big success after being overlooked.
- Nobody expected much from the little game, but it turned into a sleeper success.
- Critics ignored the book at first, yet it became a sleeper favorite with readers.
- The low-budget film became a sleeper hit, earning ten times its budget.
noun (British) A wooden or concrete beam laid under railway tracks to support them; a railroad tie.
- Each sleeper under the rails was made of solid oak.
- Concrete sleepers last longer than wooden ones along a busy railway line.
- Workers replaced the rotting sleepers along that stretch of track.
noun A car that has been heavily modified for performance while still looking ordinary.
- The plain old station wagon was a real sleeper with a huge engine under the hood.
- Nobody at the stoplight guessed my quiet little coupe was a sleeper until the light turned green.
- His beat-up sedan was a total sleeper — it could outrun most sports cars off the line.
