voyeur is the masculine noun from the French which describes a person who obtains pleasure in observing other people's sexual acts or intimate practices.
For many people, the voyeurism (or mixoscopy) is seen as a psychopathology, which consists of a deviation from sexual behavior that is considered "normal" by the majority.
In the French language, the word voyeur it means "one who sees", and therefore describes a person who likes to observe others without participating, taking pictures or recording intimate or private moments of other individuals.
Most of the time, the voyeur he doesn't usually relate directly to the people he observes and spyes on them because it gives him some sexual pleasure. In many cases, voyeurism is an invasion of privacy, because people are observed without their consent.
The obsessive practice of voyeurism often turns into persecution, where an individual knows various details about the life of the person watching. In these cases, the voyeur can also be described as a stalker. In English the expression peeping tone is a synonym for voyeur.