playoff vs contest

playoff and contest both are nouns.

Word	Noun	Adjective	Verb	Adverb
playoff	Yes	No	No	No
contest	Yes	No	Yes	No

As nouns, contest is a hypernym of playoff; that is, contest is a word with a broader meaning than playoff:

playoff: any final competition to determine a championship
contest: an occasion on which a winner is selected from among two or more contestants

Other hypernyms of playoff include competition.

playoff (noun)	contest (noun)
any final competition to determine a championship	a struggle between rivals
	an occasion on which a winner is selected from among two or more contestants

playoff (verb)	contest (verb)
	to make the subject of dispute, contention, or litigation