sleeper

(n) a rester who is sleeping slumberer,
(n) 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
(n) an unexpected achiever of success
- the winner was a true sleeper--no one expected him to get it
(n) one of the cross braces that support the rails on a railway track
- the British call a railroad tie a sleeper
crosstie, railroad tie, tie,
(n) a passenger car that has berths for sleeping sleeping car, wagon-lit,
(n) pajamas with feet; worn by children
(n) a piece of furniture that can be opened up into a bed
(n) tropical fish that resembles a goby and rests quietly on the bottom in shallow water sleeper goby,
(n) an unexpected hit
- that movie was the sleeper of the summer

slumberer crosstie railroad tie tie sleeping car wagon-lit sleeper goby

sleepy

sleeper cell sleeper goby sleeper nest