What does sleeper hit mean?

Related questions

1. Does Royal Mail First Class deliver on Sunday?
2. How long after dispatch is delivery Amazon?
3. Is bite lipstick lead free?
4. Why is Amazon delivery so slow?
5. Is Star Wars a cult classic?
6. How long does Huda beauty take to ship?
7. What is considered a cult classic?
8. Does cult beauty have student discount?
9. Is Clueless a cult classic?
10. Does MAC lipsticks have lead in them?

Tags

1. #plays
2. #little
3. #relatively
4. #entertainment
5. #successful
6. #becomes
7. #successfully
8. #opening
9. #success
10. #period
11. #despite
12. #lacking
13. #sleeper
14. #having
15. #industry
16. #promotion