sleeper
sleep‧er /ˈsliːpə $ -ər/
noun [countable]
light sleeper (=someone who wakes easily)
heavy sleeper (=someone who does not wake easily)
2. someone who is asleep
3.
British English a heavy piece of wood or concrete that supports a railway track
SYN tie American English
4.
a. a night train with carriages that have beds for passengers to sleep in
b. a sleeping car
c. American English a bed on a train for a passenger to sleep in
5. especially American English a film, book etc which is successful, even though people did not expect it to be
6. American English a piece of clothing for a baby that covers its whole body including its feet
7. a spy who is sent to a particular place and who lives an ordinary life there until a later time, when they begin their spying activities
sleep‧er /ˈsliːpə $ -ər/
noun [countable] Word Family: noun: sleep, sleeper, sleepiness, sleeplessness; adjective: asleep, sleepless, sleepy; adverb: sleepily, sleeplessly; verb: sleep
1. someone who sleeps in a particular waylight sleeper (=someone who wakes easily)
heavy sleeper (=someone who does not wake easily)
2. someone who is asleep
3.

British English a heavy piece of wood or concrete that supports a railway track
SYN tie American English
4.
a. a night train with carriages that have beds for passengers to sleep in
b. a sleeping car
c. American English a bed on a train for a passenger to sleep in
5. especially American English a film, book etc which is successful, even though people did not expect it to be
6. American English a piece of clothing for a baby that covers its whole body including its feet
7. a spy who is sent to a particular place and who lives an ordinary life there until a later time, when they begin their spying activities