A smuggler was anyone who dealt in contraban or controlled substances during the days of the Corrinos.
Smugglers were common on the planet Arrakis. They usually dealt in the spice melange, as well as other foodstuffs and weapons.
During Harkonnen rule on Arrakis, smugglers tended to remain covert for fear of retribution. However, when House Atreides took over spice mining operations on Arrakis, Duke Leto Atreides attempted to establish detente with the smugglers, informing them that he would ignore their operations on the provision that they forwarded to Leto a percentage of their profits.
Esmar Tuek was a known spice smuggler during the time when House Atreides took over spice mining on Arrakis in 10,191 A.G.