marriage broker vs intermediary

marriage broker and intermediary both are nouns.

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

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

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

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

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