A smuggler was anyone who sold or transported contraban or controlled substances. Smuggling was common during the rule of the Corrinos, but became less practiced during the Atreides rule of Leto II, who used prescience to maintain strict rule over the Known Universe.
Smuggling on Arrakis
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.