The Ferengi were a space-faring humanoid species native to the planet Ferenginar. Ferengi civilization was built on the ideals of free enterprise, where all other goals are subjugated to the pursuit of profit. Their governing body, known as the Ferengi Alliance, was formed over a period of ten thousand years, beginning with the establishment of a system of currency, to their purchase of warp technology, and finally to its state in the 24th century. The Ferengi realize that Humans and other species often look down on them for their ravenous profiteering and lack of independent technological or cultural achievements. However, Ferengi often see other races as self-righteous and, as Ferengi have come into regular contact with Humans, their own self-image has improved by comparison. While their criticism that Humans took well over 6,000 years to develop a central banking system after the beginning of their civilization may seem lacking in moral force, other arguments can be more convincing.

On average, Ferengi were shorter than Humans. They had orange-brown colored skin, blue fingernails, enlarged skulls, wrinkled noses, and sharp teeth. Internally, they had ascending ribs and upper and lower lungs, as well as an unusual four-lobed brain that could not be read by telepathic species such as Betazoids, although Counselor Troi was able to detect "deception" and "danger" from the Ferengi Bok. Ferengi physiology was similar to that of the Dopterians, of which they were distant relatives.

The Ferengi's most distinguishing feature was their large ears (called "lobes"), which gave them extremely acute hearing. The lobes of the Ferengi male were larger than those of females. The sensitivity of the ears also made them vulnerable to pain and other problems, including severe infections of the tympanic membrane which, if left untreated, can become fatal. The ears, at least in males, are erogenous zones; Ferengi are seen to take sensual delight when their ears are stimulated, described by the word umox ("oo-mox".)

Number Rules
1 Once you have their money, you never give it back.
2 The best deal is the one that brings the most profit.
3 Never pay more for an acquisition than you have to.
6 Never allow family to stand in the way of opportunity.
7 Keep your ears open.
8 Small print leads to large risk.
9 Opportunity plus instinct equals profit.
10 Greed is eternal.
13 Anything worth doing is worth doing for money.
16 A deal is a deal.
17 A contract is a contract is a contract ... but only between Ferengi.
18 A Ferengi without profit is no Ferengi at all.
19 Satisfaction is not guaranteed.
21 Never place friendship above profit.
22 A wise man can hear profit in the wind.
23 Nothing is more important than your health ... except for your money.
27 There is nothing more dangerous than an honest businessman.
31 Never make fun of a Ferengi's mother.
33 It never hurts to suck up to the boss.
34 War is good for business
35 Peace is good for business.
40 She can touch your lobes, but never your latinum.
41 Profit is its own reward.
44 Never confuse wisdom with luck.
45 Expand or die.
47 Never trust a man wearing a better suit than your own.
48 The bigger the smile, the sharper the knife.
52 Never ask when you can take.
53 Never trust anybody taller than you.
57 Good customers are as rare as latinum. Treasure them.
58 There is no substitute for success.
59 Free advice is seldom cheap.
60 Keep your lies consistent.
62 The riskier the road, the greater the profit.
65 Win or lose, there's always Hupyrian beetle snuff.
74 Knowledge equals profit.
75 Home is where the heart is, but the stars are made of latinum.
76 Every once in a while, declare peace. It confuses the hell out of your enemies.
79 Beware of the Vulcan greed for knowledge.
82 The flimsier the product, the higher the price.
85 Never let the competition know what you're thinking.
89 Ask not what your profits can do for you, but what you can do for your profits.
94 Females and finances don't mix.
95 Expand or die.
97 Enough... is never enough.
98 Every man has his price.
99 Trust is the biggest liability of all.
102 Nature decays, but latinum lasts forever.
103 Sleep can interfere with your lust for latinum.
104 Faith moves mountains... of inventory.
106 There is no honor in poverty.
109 Dignity and an empty sack is worth the sack.
111 Treat people in your debt like family ... exploit them.
112 Never have sex with the boss's sister.
113 Always have sex with the boss.
121 Everything is for sale, even friendship.
123 Even a blind man can recognize the glow of latinum.
125 You can't make a deal if you're dead.
139 Wives serve, brothers inherit.
141 Only fools pay retail.
142 Only fools sell wholesale.
144 There's nothing wrong with charity... as long as it winds up in your pocket.
147 People love the bartender.
162 Even in the worst of times, someone turns a profit.
168 Whisper your way to success.
177 Know your enemies... but do business with them always.
- A man is only worth the sum of his possessions.
181 Not even dishonesty can tarnish the shine of profit.
189 Let others keep their reputation. You keep their latinum.
190 Hear all, trust nothing.
192 Never cheat a Klingon... unless you can get away with it.
193 It's never too late to fire the staff
194 It's always good to know about new customers before they walk in your door.
202 The justification for profit is profit.
203 New customers are like razor-toothed gree-worms. They can be succulent, but sometimes they bite back.
208 Sometimes the only thing more dangerous than a question is an answer.
211 Employees are the rungs on the ladder of success. Don't hesitate to step on them.
214 Never begin a negotiation on an empty stomach.
217 You can't free a fish from water.
218 Always know what you're buying.
219 Sometimes what you get free costs entirely too much.
223 Beware the man who doesn't make time for oo-mox.
229 Latinum lasts longer than lust.
235 Duck; death is tall.
236 You can't buy fate.
239 Never be afraid to mislabel a product.
242 More is good. All is better.
255 A wife is a luxury... a smart accountant a necessity.
261 A wealthy man can afford anything except a conscience.
263 Never let doubt interfere with your lust for latinum.
266 When in doubt, lie.
267 If you believe it, they believe it.
284 Deep down, everyone's a Ferengi.
285 No good deed ever goes unpunished.
286 When Morn leaves, it's all over.
299 After you've exploited someone, it never hurts to thank them.  That way, it's easier to exploit them next time.
305 Always be considerate. (Not a real Rule, of course, but quoted by Quark.)
Exploitation begins at home.
(The unwritten rule) When no appropriate rule applies, make one up.
When the messenger comes to appropriate your profits ... kill the messenger.
Time, like latinum, is a highly limited commodity.
Always inspect the merchandise before making a deal.
Money is money, but females are better.
Why ask, when you can take?
A good lie is easier to believe than the truth.
If that's what's written, then that's what's written.