1a person or thing that spoils something:it is a sad thing that so many so-called book lovers are book spoilers
(especially in a political context) a person who obstructs or prevents an opponent’s success while having no chance of winning a contest themselves:he is perceived as a genuine factor in the presidential election, a certified political spoiler
a news story published to divert attention from and reduce the impact of a similar item published elsewhere:the paper ran a spoiler
a description of an important plot development in a television programme, film, etc. before it is shown to the public.
2a flap on the wing of an aircraft which can be projected in order to create drag and so reduce speed.
a structure on a motor vehicle intended to improve roadholding when travelling at very high speeds.
3an electronic device for preventing unauthorized copying of sound recordings by means of a disruptive signal inaudible on the original.
spoiler in other Oxford dictionaries
Definition of spoiler in the US English dictionary