There are several synonyms for the term "exclusive mandate", including sole agency, exclusive agency, exclusive representation, and exclusive authorization. These terms refer to a contractual agreement between two parties, where one party gives the other party the exclusive right to act as their agent or representative in a particular transaction or business deal. This means that no other party can negotiate on behalf of the client in that specific transaction. The term "exclusive mandate" is commonly used in real estate and financial industries, but the synonyms could be applied in any other context where an exclusive agreement is required.