What is a counterfeit in computer science?

Counterfeit software is software which is not a genuine copy or at least not legally produced by the intellectual property owner. A counterfeit Windows CD or DVD would be pirated and sold in retail settings. They may look very close to the real thing and may contain activation cracks, and the customers might not even know they purchased a pirated copy.

Sometimes, the term is used to refer to inferior hardware components (or even entire systems) which are misbranded and passed off as better hardware. There were misbranded UART chips for modems in the 1990's which claimed to be the buffered variety but were not. While not a computer issue, the US Military complained about "counterfeit bolts" in the late 1980's. They were either stamped as being a better alloy and grade than they were, or they were broken bolts which were "repaired" using glue. Sometimes computer parts and even entire computers are not only of inferior quality, but completely fake as in the Adaptec hard drive scandal and in reported cases of laptop sales fraud on eBay. Literal masonry bricks were shipped in place of hard drives and laptop computers.