Voyeurism

To be a voyeur is to have a sexual interest in observing others or to be actively involved in the erotic surveillance of them. The desire at work in voyeurism ( from the French voyeur, “ one who looks”) is to enjoy the spectacle of someone who is undressing or-ideally-if they are engaged in sexual activity.
The pleasure of the voyeur can also be encouraged by any intimate activity assumed to be private at the moment it is being watched. This could take the form of the target trying clothes on, brushing hair or cooking. In these moments, the objectified centre of the voyeuristic spectacle will, most likely, be unaffected, unguarded and entirely natural in their behaviour.
In popular imagination the term voyeurism can be applied in a more general sense to refer to someone who habitually observes others without their knowledge regardless of any sexual interest. They may do this by using a number of strategies-observing their subject from a distance using a camera with a zoom lens, or closer up with the use of peep-holes, two way mirrors or concealed cameras.
An interesting variation on this kink is the phenomenon of consensual fetishism when the person being observed is always aware that the voyeur is watching them and finds their own fetishistic value in it.