The Oxford Thesaurus An A-Z Dictionary of Synonyms - liaison n.

1) connection, communication, contact, linkage, affiliation, relationship, relations: Liaison between the ministries is improving. 2) contact, intermediary, link, tie, medium, go-between, agent: She acts as liaison between the heads of research and manufacturing. 3) (love) affair, amour, relationship, affaire d'amour, affaire de coeur, intrigue, romance, entanglement, flirtation: David's wife soon found out about his liaison with the girl in the typing pool.