A false positive is another way of saying mistake.
As applied to the field of anti-malware programs, a false positive occurs when the program mistakenly flags an innocent file as being infected.This may seem harmless enough, but false positives can be a real nuisance.
The term is not confined just to the anti-malware world. It also applies, for example, to anti-spam protection, where it refers to the misidentification of a legitimate e-mail message as spam.
This too could be very costly, since the undelivered e-mail may be a business critical message.