a candidate with no chance of winning but who may draw enough votes to prevent one of the leading candidates from winning
"The third-party spoiler cost the incumbent re-election by splitting the progressive vote."
someone who pampers or spoils by excessive indulgence
"The new mother acted like a total spoiler, buying her toddler every candy bar in sight and never letting him cry for even a second."
an airfoil mounted on the rear of a car to reduce lift at high speeds
"The aerodynamicist adjusted the spoiler on the race car's trunk to ensure maximum downforce during every cornering maneuver."
a hinged airfoil on the upper surface of an aircraft wing that is raised to reduce lift and increase drag
"The pilot deployed the spoiler on the right wing immediately after takeoff to help slow the plane down before landing."
One who spoils; a plunderer; a pillager; a robber; a despoiler.
"The bandits were not just thieves, but true spoilers who stripped the village of every loaf of bread and piece of cloth they could find."
To mark (a document or message) with a spoiler warning, to prevent readers from accidentally learning details they would prefer not to know.
"Before you read the rest of the email, I added a spoiler warning so you don't find out who betrayed the team by accident."