a description of an important plot development in a television show, film, or book which if previously known may reduce surprise or suspense for a first-time viewer or reader

a person or thing that spoils something

it is a sad thing that so many so-called book lovers are book spoilers

a flap on the wing of an aircraft that can be projected in order to create drag and so reduce speed

an electronic device for preventing unauthorized copying of sound recordings by means of a disruptive signal inaudible on the original