sleeper
n. countablen. something that becomes successful or popular after a long time of being ignored. It can also mean a person who is sleeping or a train car with beds.
n. a person or thing that achieves unexpected success after an initial period of obscurity. In a literal sense, refers to a person who is asleep or a railway vehicle with sleeping berths.
The low-budget movie became a sleeper hit after several months.
Critics ignored the novel when it first came out, but it proved to be a sleeper and topped the charts a year later.
While the blockbuster failed to meet expectations, the independent documentary emerged as a sleeper, gaining momentum through word-of-mouth recommendations and eventually securing a national theatrical release.
From Middle English sleper, equivalent to sleep + -er.
Compare Norwegian sleip (“a sleeper (a timber); as adjective, slippery, smooth”). See slape.
Commonly used in the compound 'sleeper hit' to describe media that finds a late audience.