Information about a game that someone who hasn't played it wouldn't know, particularly if knowing that information beforehand would affect their playing experience, 'spoiling' the game for them. Spoilers should be kept on the channel for the relevant game, in the spoiler room southeast of the lounge, or on the #spoilers channel (with due warning).
A message that will give away a surprise contained in a book, movie, television series or game.
A spoiler is either a comment or a picture that can help give away the location or surprise of a cache. The only person that should place a spoiler on a web site is the cache originator. When logging your cache finds on the internet, please try not to include information that might spoil the fun of finding the cache or surprise for someone else.