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
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 plural
6
chiefly British
: a small earring or stud worn to keep the hole of a pierced ear from closing
Cite this Entry
“Sleeper.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sleeper. Accessed 1 Sep. 2026.
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