WordWeb Online

1. Someone who is sleeping
   - slumberer
    
2. A spy, saboteur or terrorist planted in an enemy country who lives there as a law-abiding citizen until activated by a prearranged signal
    
3. An unexpected achiever of success
   "the winner was a true sleeper--no one expected him to get it"
    
4. [Brit] One of the cross braces that support the rails on a railway track
   "the British call a railway tie a sleeper";
   - tie [N. Amer], railroad tie [N. Amer], crosstie [N. Amer]
    
5. A passenger car that has berths for sleeping
   - sleeping car, wagon-lit
    
6. [N. Amer] Pyjamas with feet; worn by children
    
7. [N. Amer] A piece of furniture that can be opened up into a bed
    
8. Tropical fish that resembles a goby and rests quietly on the bottom in shallow water
   - sleeper goby
    
9. An unexpected hit
   "that movie was the sleeper of the summer"
    
10. A structural beam in a floor

Derived forms: sleepers

Type of: achiever, article of furniture, bang [informal], brace, bracing, carriage, coach, diversionist, furniture, hit, jammies [N. Amer, informal], jim-jams [Brit, informal], pajama, passenger car, percoid, percoid fish, percoidean, piece of furniture, pj's [informal], pyjama, rester, saboteur, sizzler [informal], smash, smasher [informal], spy, strike, succeeder, success, terrorist, undercover agent, winner, wrecker

Part of: Eleotridae, family Eleotridae, railroad [N. Amer], railroad track [N. Amer], railway [Brit, Cdn], railway track [Brit, Cdn], sleeper nest

Encyclopedia: Sleeper, Thomas