reliever vs twirler

reliever and twirler both are nouns.

Word	Noun	Adjective	Verb	Adverb
reliever	Yes	No	No	No
twirler	Yes	No	No	No

As nouns, twirler is a hypernym of reliever; that is, twirler is a word with a broader meaning than reliever:

Other hypernyms of reliever include hurler, pitcher.

reliever (noun)	twirler (noun)
a pitcher who does not start the game	(baseball) the person who does the pitching
someone who takes the place of another (as when things get dangerous or difficult)	someone who twirls a baton
a person who reduces the intensity (e.g., of fears) and calms and pacifies