campaigner vs spoiler

campaigner and spoiler both are nouns.

Word	Noun	Adjective	Verb	Adverb
campaigner	Yes	No	No	No
spoiler	Yes	No	No	No

As nouns, spoiler is a hyponym of campaigner; that is, spoiler is a word with a more specific, narrower meaning than campaigner:

campaigner: a politician who is running for public office
spoiler: a candidate with no chance of winning but who may draw enough votes to prevent one of the leading candidates from winning

Other hyponyms of campaigner include dark horse, favorite son, running mate, stalking-horse, write-in, write-in candidate.

campaigner (noun)	spoiler (noun)
a politician who is running for public office	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
	someone who takes spoils or plunder (as in war)
	a candidate with no chance of winning but who may draw enough votes to prevent one of the leading candidates from winning
	someone who pampers or spoils by excessive indulgence