sleeper /ˈsliːpə(ɹ)/noun 18verb 1forms 3phrases 1 noun18 •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. •A railway sleeping car.We spent a night on an uncomfortable sleeper between Athens and Vienna. •(UK) A railroad tie.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. — 2009 •A structural beam in a floor running perpendicular to both the joists beneath and floorboards above. •A heavy floor timber in a ship's bottom. •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. •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 […] — 1625 •A spy, saboteur, or terrorist who lives unobtrusively in a community until activated by a prearranged signal; may be part of a sleeper cell. •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. •(slang) A sedative.At least a couple of weeks since I last slept, / Kept takin' sleepers, but now I keep myself pepped. — 1995 •A sleeper hold.Detailed floral stripe on sofas, sleepers and loveseats with correlating provincial print on double ruffle trim. — 1980 •(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. •A small starter earring, worn to prevent a piercing from closing. •A pod or similar device containing a person in cryosleep. •Any member of the family Odontobutidae of goby-like bottom-feeding freshwater fish. •A nurse shark (family Ginglymostomatidae). •(slang) A bet placed on the gambling table and then forgotten about by the gambler. •The lowest, or bottom, tier of casks. verb1 •(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. — 1963 formssleepered · sleepering · sleepers Phrases with sleeper rough sleeperA homeless person who sleeps outdoors.