1. Person or thing that spoils.
2. A person who robs or ravages; despoiler; plunderer.
3. Aeronautics. A device used to break up the airflow around an aerodynamic surface, as an aircraft wing, in order to slow the movement through the air or to decrease the lift on the surface and, as a result, provide bank or descent control.
4. Automotive. a similar device for changing the airflow past a moving vehicle, often having the form of a transverse fin or blade mounted at the front or rear to reduce lift and increase traction at high speeds.
5. Sports. A team out of final contention that defeats a potential or favored contender and thereby thwarts its chances of winning a championship.
6. Any competitor, entrant, or candidate who has no chance of ultimate victory but does well enough to spoil the chances of another.
7. An important plot point/s or moment/s being described that could spoil the contents of a story to another member of the audience that has not gotten that far in the narrative.
EX. I'm only about four or five seasons into Breaking Bad. I'm a new fan. Please, no spoilers.