marriage broker vs mediator

marriage broker and mediator both are nouns.

Word	Noun	Adjective	Verb	Adverb
marriage broker	Yes	No	No	No
mediator	Yes	No	No	No

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

marriage broker: someone who arranges (or tries to arrange) marriages for others
mediator: a negotiator who acts as a link between parties

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

marriage broker (noun)	mediator (noun)
someone who arranges (or tries to arrange) marriages for others	a negotiator who acts as a link between parties