One who acts as an intermediary or messenger between two sides.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "go-between" in a sentence
"All this he said in the High, except for the word go-between: kynamolgos."
"The three play different aspects of the Chevalier d'Éon, as well as two kings, a queen, doctors, narrators, a political go-between, a rival swordsman and a horse."
"She will be a priceless go-between for Obama to Congress in the hard battles that he will continue to face to get his agenda passed."