agent
arbitrator
bargainer
broker
business agent
cardholder
connection
contact
deputy
front
front man
go-between
interagent
interceder
intercessor
intermediary
intermediate
intermediate agent
intermediator
intermedium
internuncio
interpleader
intervener
interventionist
interventor
labor organizer
mediator
medium
middleman
mouthpiece
negotiant
negotiatress
negotiatrix
ombudsman
organizer
shop steward
spokesman
spokeswoman
trade unionist
union member
union officer
unionist
communicator
compromiser
holdout
representative
settler
adviser
airman
architect
businessman
consulate
delegation
diplomat
diplomatist
economist
embassy
envoy
interrogator
journalist
law-makers
mathematician
psychiatrist
researcher
strategist
tactician