A smuggler is a person that secretly transports goods or persons past a point where prohibited in violation of the law or other rules.
Amarie's husband, a weapons smuggler, was killed when his ship attacked the USS Enterprise-D in 2368. (TNG: "Unification II")
DaiMon Solok agreed to smuggle a Starfleet commando squad onto Celtris III after some convincing from Beverly Crusher. (TNG: "Chain of Command, Part I")
While traveling under the alias of Galen in 2370, Captain Jean-Luc Picard claimed that he was a smuggler who had had dealings with Starfleet. (TNG: "Gambit, Part I")
A group of Subytts attempted to smuggle defected isolinear rods to Bajor in late 2369/early 2370. (DS9: "The Homecoming")
Razka Karn was a smuggler, thief and black marketeer with at least twelve outstanding warrants for his arrest on Cardassia as of 2372. (DS9: "Indiscretion")
Also that year, Kasidy Yates was caught smuggling medical supplies to the Maquis by her lover Benjamin Sisko. She did not realizing that doing so was part of a scheme to lure Sisko away from Deep Space 9 so Maquis agent Michael Eddington could steal Industrial replicators from the station. (DS9: "For the Cause")
Bajoran Latha Mabrin was a smuggler and an arms dealer during the Occupation of Bajor before he found the Prophets and became a Vedek. (DS9: "The Darkness and the Light")