peacemaker vs mediator

peacemaker and mediator both are nouns.

Word	Noun	Adjective	Verb	Adverb
peacemaker	Yes	No	No	No
mediator	Yes	No	No	No

As nouns, mediator is a hypernym of peacemaker; that is, mediator is a word with a broader meaning than peacemaker:

Other hypernyms of peacemaker include go-between, intercessor, intermediary, intermediator.

peacemaker (noun)	mediator (noun)
someone who tries to bring peace	a negotiator who acts as a link between parties