Spoiler

A Spoiler is information about a series, movie, or show that might not have become commonplace and that not everyone might know. This can sometimes be a problem in a fast moving fandom after a new release, when people do not make note of spoilers in discussions or fanfic, and thus ruin the enjoyment of finding out themselves for other people.

Conversely, some people thrive on spoilers, both in reading them or giving them.