sleeper

a rester who is sleeping

one of the cross braces that support the rails on a railway track

“the British call a railroad tie a sleeper”

tropical fish that resembles a goby and rests quietly on the bottom in shallow water

a passenger car that has berths for sleeping

an unexpected achiever of success

“the winner was a true sleeper--no one expected him to get it”

an unexpected hit

“that movie was the sleeper of the summer”

a piece of furniture that can be opened up into a bed

a spy or saboteur or terrorist planted in an enemy country who lives there as a law-abiding citizen until activated by a prearranged signal

pajamas with feet; worn by children