super-sleeper

noun5

1. •
   A high-performance car that has an unassuming appearance.

   • One of the supersleepers. Its slant-six engine made the Ark look flimsy; it would almost literally run forever, and Dodge pick-ups with the same engine have gone 160,000 miles with no teardown. — 1977
2. •
   Someone or something that does not seem very impressive at first but that goes on to become a star.

   • You have your cheat sheets ready, your blank draft board prepared, and your super sleeper picks marked in red. — 2007
3. •
   One who is particularly good at falling asleep.

   • Supersleepers are the undisputed stars of Babyville. They're the invants who fall asleep happily, independently, consistently. — 2009
4. •
   An extremely efficient sleeper who does not require much sleep.

   • Some "supersleepers" need only three or four hours. Research has shown that these people sleep more efficiently. — 1982
5. •
   A luxury vehicle that allows passengers to sleep.