(1):

(v. t.) One who transacts business for another; an agent.

(2):

(v. t.) A dealer in money, notes, bills of exchange, etc.

(3):

(v. t.) An agent employed to effect bargains and contracts, as a middleman or negotiator, between other persons, for a compensation commonly called brokerage. He takes no possession, as broker, of the subject matter of the negotiation. He generally contracts in the names of those who employ him, and not in his own.

(4):

(v. t.) A dealer in secondhand goods.

(5):

(v. t.) A pimp or procurer.