| conciliator(noun, authority, advocate, judge, expert) |
| connection(noun, person, link, contact, relative) |
| instrumentality(noun, means, channel, medium) |
| interagent(noun, person) |
| intermedium(noun, interposition) |
| liminal |
| mechanism(noun, means, channel, medium) |
| median(noun, adjective, middle) |
| mid(mean, middle, midway, midpoint, transitional) |
| midway(adjective, mean, middle, midpoint, transitional) |
| ombudsman(noun, authority, agent, expert, court) |
| operative(noun, adjective, agent, representative, manager) |
| surrogate(noun, agent, substitute, representative, operative) |
| tool(noun, person, means, channel, medium) |
| actor(noun, agent, representative, operative, manager) |
| ambassador(noun, substitute, representative, assistant, operative) |
| appeaser |
| contact(noun, communication, connection, link, relative) |
| diplomat(noun, representative, deputy, herald, minister) |
| go between(expression, idiom, interposition) |