sleeper

noun

1. Someone who sleeps.

   “I'm a light sleeper: I get woken up by the smallest of sounds.”

   “She's a heavy sleeper: it takes a lot to wake her up.”

   “Waveless mattresses are for those who prefer a more stationary [night's sleep]; semiwaveless for those who want a slight rocking motion, and free-flow for sleepers who want the feel of a boat. All beds come with temperature controls, and king- and queen-size models offer dual controls.”

2. That which lies dormant, as a law.

   “Therefore let penal laws, if they have been sleepers of long, or if they be grown unfit for the present time, be by wise judged confined in the execution […]”

   “The object of these provisions is to prevent insertion of "jokers" or "sleepers" in bills and securing passage under the false color of the title.”

3. A spy, saboteur, or terrorist who lives unobtrusively in a community until activated by a prearranged signal; may be part of a sleeper cell.

   “We are up against the pros; and pros who have been involved in this kind of activity for many years. […] The public apathy today is disturbing — few realize, Mr. Chairman, that there are sleepers in this country and we know that they are able to manipulate at will behind the scenes.”

4. A small starter earring, worn to prevent a piercing from closing.

   “His skull earring had been replaced by a small gold sleeper. […] Fiona, who also had pierced ears, remarked on his sleeper. “Doesn’t Wilton allow pierced ears?” she asked. “No way!” said Leslie. “Rules about everything. But I wanted to keep my options open, as you might say. No one’s made me take it out yet. […]””

5. A railway sleeping car.

   “We spent a night on an uncomfortable sleeper between Athens and Vienna.”

   “It is realised that the old Pullman standard sleeper, with its convertible "sections", each containing upper and lower berths, and with no greater privacy at night than the curtains drawn along both sides of a middle aisle, has had its day.”

6. A sleeper hold.
7. Something that achieves unexpected success after an interval of time.

   “A box-office bomb when it first came out, the film was a sleeper, becoming much more popular decades after being released.”

   “For example, the [racehorse] trainer may have tipped a betting syndicate that he is about to unleash a sleeper […]”

8. Any of family Odontobutidae of goby-like bottom-feeding freshwater fish.
9. A nurse shark (family Ginglymostomatidae).
10. A type of pajama for a person, especially a child, that covers the whole body, including the feet.

    “Aaron, Devin, and Laura looked so comfy in their sleepers.”

11. (slang)An automobile which has been internally modified to excess, while retaining a mostly stock appearance in order to fool opponents in a drag race, or to avoid the attention of the police.
12. (slang)A sedative.

    “At least a couple of weeks since I last slept, / Kept takin' sleepers, but now I keep myself pepped.”

13. (slang)A bet placed on the gambling table and then forgotten about by the gambler.
14. A pod or similar device containing a person in cryosleep.
15. (British)A railroad tie.

    “The train, minus the three abandoned trucks, again proceeded at a slow pace, with a pump trolley doing pilot ahead ; this was very necessary as a great many sleepers were found to have been burnt underneath the fishplates.”

    “I should imagine that the smooth riding and the quietness of the diesel or electric cab, coupled with the effect on the eyes of endless successions of sleepers disappearing from sight immediately under the driver's eyes, might in time have a soporific effect, so that the company of a second man, who can assist in signal observations when he is not at work in the engine cab, seems highly desirable in such conditions.”

    “Government surveyors set to work, importing hundreds of Indian coolies, thousands of donkeys and camels, and the millions of sleepers required for this monstrous engineering project.”

16. A structural beam in a floor running perpendicular to both the joists beneath and floorboards above.
17. A heavy floor timber in a ship's bottom.
18. The lowest, or bottom, tier of casks.

verb

1. (rare)To mark a calf by cutting its ear.

   “I expect there ain't a trick to maverickin' and sleeperin' and changin' a brand he don't know.”

name

1. A surname.