reliever vs actor

reliever and actor both are nouns.

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

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

reliever: a person who reduces the intensity (e.g., of fears) and calms and pacifies
actor: a person who acts and gets things done

Other hypernyms of reliever include doer, worker.

reliever (noun)	actor (noun)
a pitcher who does not start the game	a theatrical performer
someone who takes the place of another (as when things get dangerous or difficult)	a person who acts and gets things done
a person who reduces the intensity (e.g., of fears) and calms and pacifies