intermediary vs intercessor

intermediary and intercessor both are nouns.

Word	Noun	Adjective	Verb	Adverb
intermediary	Yes	No	No	No
intercessor	Yes	No	No	No

As nouns, intermediary and intercessor are synonyms defined as:

intermediary and intercessor: a negotiator who acts as a link between parties

Other synonyms of intermediary include go-between, intermediator, mediator.

intermediary (noun)	intercessor (noun)
a negotiator who acts as a link between parties	a negotiator who acts as a link between parties