Go-between
(n.)
An intermediate agent; a broker; a procurer; -- usually in a disparaging sense.
Webster's Revised Unabridged Dictionary (1913), edited by Noah Porter.
About
go-between
Noun
1. a negotiator who acts as a link between parties
(synonym) mediator, intermediator, intermediary, intercessor
(hypernym) negotiator, negotiant, treater
(hyponym) mediatrix