The Ferengi were an invention of Gene Roddenberry himself to replace the Klingon empire as the "enemy" race of the Federation in TNG. Their name likely is derived from the Arabic word Faranj or Ifranj, "Franks", which the Arabs used to describe the European merchants in the Mediterranean Sea and Indian Ocean and by extension, all westerners.

Therefore Roddenberry wants to make fun about the European Union, which just wanted to be an economical power equal to the United States of America.

In Star Trek the Ferengi are a spacefaring humanoid species native to the planet Ferenginar. Ferengi civilization is built on the ideals of pure laissez-faire capitalism, where all other goals are subjugated to the pursuit of profit.

Ferengi culture is extremly patriarchal. Females are bought and sold and kept unclothed. (TNG: "Menage a Troi")

As the federation grow, they reached new far away empires. Now they had to confront these new, powerfull and very angerous enemys. The Ferengi are on the same technological level as the others - or maybe they are even more dangerous, because they knew no moral and ethics as we know. "The Federation found the first reference to the Ferengi approximately 50 years ago. Their alliance works with political and economical pressure and suffocates independence efforts in the germ with military forces." (see TNG 1st season: Encounter at Farpoint, p.118) That must have been arround the year 2314.

Picard says: "I already know about the activities of the Ferengi for more than 25 years" (see TNG 1st season: Encounter at Farpoint, p.117) - therefore he heard about them before 2339.

But 2355 in the Maxia Zeta system the Federation starship USS Stargazer, under the command of Captain Jean-Luc Picard, was attacked by an unknown vessel. Nine years later, the attacker was found to be a Ferengi vessel, commanded by DaiMon Bok's son. (see 1st season TNG: The Battle)

Since then, the Ferengi have shown themselves an extremly greedy, capitalsitic people who are motivated purely by a desire for profit. They have shown warp drive capability and a technology on roughly the same level as the Federation.

They are realy dangerous and are living on severall planets. Me know for sure from the fourth planet in the Lappa system, which s the native world of the flower Zan Periculi. (see TNG: Menage a Troi)