A spoiler is also a piece of information about a book, TV show, cartoon, movie, or other entertainment media work which gives away information about the middle or end of the work. It is generally considered to be good courtesy not to put up spoiling information, or at least to head it up with "This is a spoiler" or something.

An example:
*** Spoiler Below ***

You're going to die.

A spoiler is also a thing, horizontally affixed to the trunk or rear of a car, which ostensibly provides a downward force to counter the car's tendancy to lift slightly at high speeds. That, and they usually make the car look trés cool.

In aviation, a spoiler is a device which reduces the aerodynamic efficiency of the aircraft for the purpose of increasing glide angle or dive speed. Two primary types of spoilers are used:
• A surface normally flush to the top surface of each wing which pivots at the forward edge.
• A surface perpendicular to the airflow which can be extended from within the wing through a slot in the top surface.

The spoilers work by disrupting the airflow across the wing, increasing parasitic drag, which reduces the lift to drag ratio (L/D). The lift-to-drag ratio translates inversely to glide angle. All else being equal, an aircraft with spoilers deployed will descend faster than the same aircraft without them deployed.

Spoilers are most often employed in high-performance sailplanes so they can escape strong lift and so that they can be brought down quickly without resorting to dangerous airspeeds. Spoilers are deployed symmetrically, i.e. by the same amount on each wing at the same time.
spod = S = spoiler space

spoiler n.

[Usenet] 1. A remark which reveals important plot elements from books or movies, thus denying the reader (of the article) the proper suspense when reading the book or watching the movie. 2. Any remark which telegraphs the solution of a problem or puzzle, thus denying the reader the pleasure of working out the correct answer (see also interesting). Either sense readily forms compounds like `total spoiler', `quasi-spoiler' and even `pseudo-spoiler'.

By convention, articles which are spoilers in either sense should contain the word `spoiler' in the Subject: line, or guarantee via various tricks that the answer appears only after several screens-full of warning, or conceal the sensitive information via rot13, spoiler space or some combination of these techniques.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

Spoil"er (?), n.

1.

One who spoils; a plunderer; a pillager; a robber; a despoiler.

2.

One who corrupts, mars, or renders useless.