Con artist
A con artist or confidence man, also known as a flim-flam man or flim-flam artist, was a person who gained another's confidence through trickery, then exploited that trust for his or her own gain. This was a form of fraud. A hustler was another type of con artist.

Harry Mudd was a notorious con artist in the late 23rd century. (; )

Captain Jean-Luc Picard once referred to Q as a "flim flam man". Worf, however, did not understand the term. ()

In 2367, a  attempted to trick the inhabitants of Ventax II into believing that she was Ardra, an equivalent of the Devil. As the crew of the  became embroiled in her scheme, Picard told Data that he had been examining the dynamics of what had once been known as the "con game." He described it as a fascinating subject, worthy of his study. ()

Quark told Odo that he would have every confidence man aboard Deep Space 9 by the next day after he heard that Odo was temporarily relieved from duty. ()

Martus Mazur was an El-Aurian con artist who used his natural powers to con a variety of people on Deep Space 9 in 2370, including Alsia and Roana. Quark saw past his charms and realized he was a con artist. ()

Odo's official report on Quark described the Ferengi as "a self-important con artist who's nowhere near as clever as he thinks he is." ()

The Ferengi Arridor and  conned the people of a primitive Delta Quadrant planet into thinking that the two Ferengi were the Holy Sages, demigods spoken of in the epic poem Song of the Sages. The crew of the  put a stop to this after Commander Chakotay and  Tom Paris discovered the exploitation while investigating the possible presence of a wormhole to the Alpha Quadrant, as well as the signature of a replicator from the Alpha Quadrant. ()

Dala, Mobar, and Zar were con artists who in 2376 impersonated Captain Kathryn Janeway, Lieutenant Commander Tuvok, and Commander Chakotay, respectively, in a string of fly-by-night scams. ()

In 2377 Gar, a con artist and swindler, stole The Doctor's hologram. ()

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Illegal occupations