n.
Pronunciation: ' sl ē -p ə r
Function: noun
Date: 12th century
1 : one that sleeps
2 : a piece of timber, stone, or steel on or near the ground to support a superstructure, keep railroad rails in place, or receive floor joists : STRINGPIECE
3 : SLEEPING CAR
4 : someone or something unpromising or unnoticed that suddenly attains prominence or value <the low-budget film became the summer's sleeper >
5 : children's pajamas usually with feet ― usually used in plural
6 chiefly British : a small earring or stud worn to keep the hole of a pierced ear from closing
7 : MOLE 4