· a rester who is sleeping

Synonym(s): slumberer

Hypernym(s): rester

· 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

Hypernym(s): spy, undercover_agent, saboteur, wrecker, diversionist, terrorist

· an unexpected achiever of success; "the winner was a true sleeper--no one expected him to get it"

Hypernym(s): achiever, winner, success, succeeder

· one of the cross braces that support the rails on a railway track; "the British call a railroad tie a sleeper"

Synonym(s): tie, railroad_tie, crosstie

Hypernym(s): brace, bracing

· a passenger car that has berths for sleeping

Synonym(s): sleeping_car, wagon-lit

Hypernym(s): passenger_car, coach, carriage

· pajamas with feet; worn by children

Hypernym(s): pajama, pyjama, pj%27s, jammies

· a piece of furniture that can be opened up into a bed

Hypernym(s): furniture, piece_of_furniture, article_of_furniture

· tropical fish that resembles a goby and rests quietly on the bottom in shallow water

Synonym(s): sleeper_goby

Hypernym(s): percoid_fish, percoid, percoidean

· an unexpected hit; "that movie was the sleeper of the summer"

Hypernym(s): hit, smash, smasher, strike, bang