reliever vs allayer

reliever and allayer both are nouns.

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

As nouns, reliever and allayer are synonyms defined as:

reliever and allayer: a person who reduces the intensity (e.g., of fears) and calms and pacifies

Other synonyms of reliever include comforter.

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