interposer

one who works with opposing sides in order to bring about an agreement I hope that we can resolve this dispute by ourselves, without the help of some outside interposer Synonyms broker, buffer, conciliator, go-between, honest broker, interceder, intercessor, intermediary, intermediate, mediator, middleman, peacemakerRelated Words troubleshooter; moderator; bargainer, negotiant, negotiator; appeaser, pacificator, pacifier, reconciler; agent, attorney, deputy, factor, procurator, proxy; liaison, medium; ambassador, emissary, envoy, legate, messenger; delegate, representative; busybody, interferer, meddler; arbiter, arbitrator, judge, referee, umpire; adviser (also advisor), counselor (or counsellor)