Definitions from Wiktionary ( )

▸ noun:  Someone who sleeps.
▸ noun:  That which lies dormant, as a law.
▸ noun:  A spy, saboteur, or terrorist who lives unobtrusively in a community until activated by a prearranged signal; may be part of a sleeper cell.
▸ noun:  A small starter earring, worn to prevent a piercing from closing.
▸ noun:  A railway sleeping car.
▸ noun:  (martial arts, wrestling) A sleeper hold.
▸ noun:  Something that achieves unexpected success after an interval of time.
▸ noun:  Any of family Odontobutidae of goby-like bottom-feeding freshwater fish.
▸ noun:  A nurse shark (family Ginglymostomatidae).
▸ noun:  A type of pajama for a person, especially a child, that covers the whole body, including the feet.
▸ noun:  (automotive, 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.
▸ noun:  (slang) A sedative.
▸ noun:  (slang, gambling) A bet placed on the gambling table and then forgotten about by the gambler.
▸ noun:  (science fiction) A pod or similar device containing a person in cryosleep.
▸ verb:  (rare) To mark a calf by cutting its ear.
▸ noun:  (rail transport, British) A railroad tie.
▸ noun:  (carpentry) A structural beam in a floor running perpendicular to both the joists beneath and floorboards above.
▸ noun:  (nautical) A heavy floor timber in a ship's bottom.
▸ noun:  (nautical) The lowest, or bottom, tier of casks.
▸ noun:  A surname.

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