overtime vs tiebreaker

overtime and tiebreaker both are nouns.

Word	Noun	Adjective	Verb	Adverb
overtime	Yes	No	No	Yes
tiebreaker	Yes	No	No	No

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

Other hyponyms of overtime include extra innings, overtime period, sudden death.

overtime (noun)	tiebreaker (noun)
playing time beyond regulation, to break a tie	overtime play in order to break a tie; e.g. tennis and soccer
work done in addition to regular working hours

overtime (adverb)	tiebreaker (adverb)
beyond the regular time