Spoiler could refer to

• Plot spoiling: a document, review, or comment which discloses plot details of a book, play, or film.
• In aeronautics: a device to reduce lift.
• In automotive technology: a device to reduce lift and increase downforce.
• In politics or gaming: an individual unable to win an election or game for him- or herself, but with the power to determine which player among two or more others does win. In politics, a spoiler is one who takes votes away from a candidate to a disproportionate degree, making certain or likely the election of a third candidate who is less acceptable or totally unacceptable to the backers of the spoiler. Political primaries are full of spoiler candidates. In general elections, discussion of third party candidates often focuses on whether or not they will be spoilers. See also spoiler effect.

Proper nouns:

• A popular calypso singer named Mighty Spoiler, sometimes known as "Spoiler".
• The Spoiler, a secondary character in the DC Comics comic book Robin.
• The SPOILER Comedy Film Project in New York City. See spoilerfilms.com