According to Wikipedia, a counterfeit is an imitation, usually one that is made with the intent of fraudulently being passed off as genuine. Counterfeit products are often produced with the intent to take advantage of the established worth of the imitated product. The word counterfeit frequently describes both the forgeries of currency and documents, as well as the imitations of clothing and accessories, software, and other brands. In the case of goods, it results in patent infringement or trademark infringement. The counterfeiting of money is usually attacked aggressively by governments. The counterfeiting of goods is countenanced by some governments.

The spread of counterfeit goods (commonly called "knockoffs") has become global in recent years and the range of goods subject to infringement has increased significantly. Apparel and accessories accounted for over 50 percent of the counterfeit goods seized by U.S Customs and Border Control. According to the study of Counterfeiting Intelligence Bureau (CIB) of the International Chamber of Commerce (ICC), counterfeit goods make up 5 to 7 percent of world trade, however these figures cannot be substantiated due to the secretive nature of the industry.

Some see the rise in counterfeiting of goods as being related to globalization. As more and more companies, in an effort to increase profits, move manufacturing to cheaper labor markets, areas with weaker labor laws or environmental regulations, they give the means of production to foreign workers. These new managers of production have little or no loyalty to the original corporation. They see that profits are being made by the global brand for doing little (other than advertising) and see the possibilities of removing the middle men (i.e. the parent corporation) and marketing directly to the consumer.

Most counterfeit goods are produced in China, making it the counterfeit capital of the world. In fact, the counterfeiting industry accounts for 8% of China's GDP. Joining China are North Korea and Taiwan. Some counterfeits are produced in the same factory that produces the original, authentic product, using the same materials. The factory owner, unbeknownst to the trademark owner, orders an intentional 'overrun'. Without the employment of anti-counterfeiting measures, identical manufacturing methods and materials make this type of counterfeiting impossible to distinguish from the authentic article. Such counterfeit articles will thoroughly deceive even the informed consumer, but harm primarily the trademark owner (although the consumer's warranty, if such is provided, may be invalid).

A federal crackdown on counterfeit imports is driving an increase in domestic output of fake merchandise, according to investigators and industry executives. Raids carried out in New York City resulted in the seizure of an estimated $200 million in counterfeit apparel, bearing the logos of brands such as "The North Face", "Polo", "Lacoste", "Rocawear", "Seven for all Mankind" and "Fubu". One of the largest seizures was a joint operation in Arizona, Texas, and California that seized 77 containers of fake "Nike Air Jordan" shoes and a container of "Abercrombie & Fitch" clothing, valued at $69.5 million. Another current method of attacking counterfeits is at the retail level. Fendi sued the "Sam's Club" division of  Wal-Mart Stores, Inc. for selling fake "Fendi" bags and leather goods. Sam's Club agreed to pay Fendi a confidential amount to settle the dispute and dismiss the action. Tiffany & Co. sued online auction site eBay for allowing the sale of counterfeit items and Gucci filed suit against 30 websites in the United States and is currently in the process of suing one hundred more.

A number of companies involved in the development of anti-counterfeiting and brand protection solutions have come together to form special industry-wide and global organizations dedicated to combating the so-called "brand pirates." These are the International Authentication Association and the International Hologram Manufacturers Association. To try to avoid this, companies may have the various parts of an item manufactured in independent factories and then limit the supply of certain distinguishing parts to the factory that performs the final assembly to the exact number required for the number of items to be assembled (or as near to that number as is practicable) and/or may require the factory to account for every part used and to return any unused, faulty or damaged parts. To help distinguish the originals from the counterfeits, the copyright holder may also employ the use of serial numbers and/or holograms etc., which may be attached to the product in another factory still.

Of course, Apparel Search is against counterfeit goods.  Don't buy a knockoff.