A post to a newsgroup or mailing list that reveals what is intended to be a surprise, such as a plot twist in a film or television episode or the solution to a game. The subject line should contain the word spoiler, but netiquette requires that the sender further protect readers who do not or cannot scan posts for subject lines in advance by encrypting the post, putting one or more screenfuls of white space above the text, or both. See also netiquette.

1. A candidate with no chance of winning but who may draw enough votes to prevent one of the leading candidates from winning.
2. A hinged airfoil on the upper surface of an aircraft wing that is raised to reduce lift and increase drag.

An airfoil mounted on the rear of a car to reduce lift at high speeds.