WordNet: negotiant, negotiator, treater

someone who negotiates (confers with others in order to reach a settlement)

• hypernym communicator

• hyponym go-between, intercessor, intermediary, intermediator, mediator

• hyponym bargainer

• hyponym compromiser

• hyponym holdout

• hyponym negotiatress, negotiatrix

• hyponym representative

• hyponym settler

negotiant

• (englanti) negotiate (derivationally related)
• (suomi) neuvottelija (synonyymi)

negotiator

• (englanti) negotiate (derivationally related)
• (suomi) välittäjä (synonyymi)

treater

• (englanti) treat (derivationally related)
• (suomi) sovittelija (synonyymi)