〈仲介〉 mediation; 【形式ばった表現】 good offices; matchmaking (縁談の)
〈仲介者〉 a mediator; an agent; an intermediary; a go‐between
【形式ばった表現】 ask somebody to use his good offices (on one's behalf)
offer oneself [put oneself forward] as go‐between [mediator] ⇒くち(口を利く).