Synonyms for sleeper

noun

• a rester who is sleeping
• one of the cross braces that support the rails on a railway track
• tropical fish that resembles a goby and rests quietly on the bottom in shallow water
• a passenger car that has berths for sleeping
• an unexpected achiever of success
• an unexpected hit
• a piece of furniture that can be opened up into a bed
• 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
• pajamas with feet; worn by children