A salesman was an individual who sold things for a living. Salesmen often targeted their customers through use of a sales pitch. (TNG: "The Arsenal of Freedom") Another term, huckster, was often used to particularly shady salesmen. (Star Trek V: The Final Frontier)
When Captain Jean-Luc Picard and Doctor Beverly Crusher were stranded on the surface of Minos, they encountered a Minosian projection that Picard identified as "the automated salesman" that had previously greeted the USS Enterprise-D after it had arrived in orbit. (TNG: "The Arsenal of Freedom")
When Quark was being recruited by his cousin Gaila, in 2373, to work for the arms dealer named Hagath, the impression Quark gave during his introduction prompted Hagath to respond, "I admire confidence in a man. In fact, I demand it of my salesmen. But in business, one must be careful not to grow too confident."
Later, after Quark sold two thousand Dopterian interceptors to an alien customer, Hagath complimented his efforts, describing the Ferengi as "a natural salesman." Quark agreed, stating that selling weapons "[i]s no different than selling sandwiches." (DS9: "Business as Usual")