A go-between (8)
I believe the answer is:
mediator
'a go-between' is the definition.
(I know that go-between can be written as mediator)
This is all the clue.
(Other definitions for mediator that I've seen before include "One seeking to reconcile opponents" , "An honest broker" , "Kind of arbitrator - one to admire" , "peacemaker" , "One intervening to settle a dispute" .)