The Star Trek usage was taken from the above usage. In the Star Trek fictional universe, the Ferengi are an alien race notable for their devotion towards profit and their constant efforts to swindle people into bad deals. They are often shown as being somewhat of a nuisance, and plots involving them are usually comedic ones. Originally, they were meant to replace the Klingons as a threat to the Federation but viewers simply could not see the ridiculous creatures as posing any kind of consistent threat. The Borg designation for the Ferengi is "species 180."
The Ferengi come from the planet Ferenginar, in the center of the Ferengi Alliance located in the Alpha Quadrant. Precisely what the Ferengi Alliance consisted of was never revealed; it may simply encompass Ferenginar and any uninhabited planets that the Ferengi have colonized, since there was little indication that the Ferengi government exercised authority over any species other than its own.
In Encounter at Farpoint the Ferengi are mentioned for the first time. The Bandi leader Groppler Zorn threatens to sell Farpoint Station to the Ferengi, to which Picard said he hoped the Ferengi found the Bandi as tasty as their last associates. The Ferengi were seen for the first time in the episode The Last Outpost. In the Star Trek chronology, the earliest known reference to the race occurs in the Star Trek: Enterprise episode "Dear Doctor" when an alien mentions the Ferengi in passing, but the Enterprise crew do not recognize the name.
Oddly enough, internal references in Star Trek: Deep Space Nine made it clear that the Klingons and the Cardassians had been interacting with the Ferengi for years prior to Encounter at Farpoint, yet apparently the Federation never received information about the Ferengi in data exchanges with either race.
Star Trek: Deep Space Nine was the series that focused most on the Ferengi; several episodes were centered around them, and the show often explored Ferengi culture in depth (and often visited Ferenginar, the Ferengi homeworld). Armin Shimerman (Quark) was a main cast member on the series.
Biology
Ferengi are somewhat smaller than humans. They have unusually large ears (more so in males than in females), sharp, crooked teeth, double foreheads, ascending ribs, upper and lower lungs, and a four-lobed brain that cannot be read by the telepathic powers of Betazoids or Vulcans. The ears, at least in males, are erogenous spots; the Ferengi colloquially use the word "lobes" much as the word "balls" is used in modern English (as in, "I didn't think you had the lobes for that"). It's not entirely clear how sharp Ferengi teeth are naturally, as within their culture it is commonplace for them to use a "toothsharpener" (sort of a cross between a power tool and an electric toothbrush) to make their teeth even sharper, which is apparently valued for its aesthetic qualities.
Culture
Ferengi culture is based entirely on commerce, and the 285 Rules of Acquisition comprise the sacred code on which all of Ferengi society is based. They were first written down by Gint, the first Grand Nagus. The title "Rules of Acquisition" was chosen as a clever marketing ploy (since the rules are merely guidelines) and Gint numbered his first rule as #162, in order to create a demand for the other 161 Rules that had not yet been created.
In addition to the Rules, the Ferengi also recognize the five Stages of Acquisition: infatuation, justification, appropriation, obsession, and resale. They value similar traits in other species as well — Earth's Wall Street is regarded with near-religious reverence by Ferengi, who routinely visit Earth to make pilgrimages to the "holy site" of commerce and business.
The laws and society of the Ferengi are extremely sexist. Women are forbidden to make profit, wear clothes, talk to strangers, or travel. Selling one's mother for gold-pressed latinum, the principal form of legal tender, is an act that would be looked on with admiration in Ferengi society.
The quest for profit even reaches into Ferengi religion. It is common for Ferengi to pray for financial success. The Ferengi believe in an afterlife which is based on the profit earned in life. There are two possible eternal fates: for the successful, the Divine Treasury or Golden Treasury lies ahead (provided one can bribe one's way in); the financial failures spend eternity in the Vault of Eternal Destitution, or Debtor's Dungeon.
Ferengi males are neither buried nor cremated when they die. Rather, the dying male puts his body up for auction to the highest bidder and the dead body is carved up into little pieces that are vacuum-desiccated, preserved and packaged for sale as mementos of a worthy life.
A subset of the Ferengi culture is known as the Eliminators, who routinely hire themselves out as assassins to anyone willing to pay for their services. Most Ferengi, however, view Eliminators as eccentric at best (since Eliminators appear to enjoy the sport of killing more than the profits gained thereby), dangerous psychopaths at worst, and avoid them whenever possible.
Ferengi cuisine consists of insects and other small invertebrates, such as "tube grubs," either served alive or jellied or juiced. Ferengi women traditionally soften food for members of their family by chewing it. Regarding the comment made by Picard in "Encounter at Farpoint" about Ferengi finding their past associates "tasty", there is no reference to whether or not these associates were insectoids. (Picard was most likely stating one of the many rumors that had risen about the Ferengi, as referenced in "The Last Outpost".)
When welcoming guests into his home, a Ferengi will speak a traditional greeting. He will say "Welcome to our home. Please place your thumbprint on the legal waivers and deposit your admission fee in the slot by the door. Remember, my house is my house." The guest replies "As are its contents."
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