Voyeurism is a practice in which an individual derives sexual pleasure from observing other people who engage in sexual acts, or are just nude or in underwear. Voyeuristic practices may take a number of forms but its characteristic feature is that the voyeur does not directly interact with the object of their voyeurism (often unaware that they are being observed), instead observing the act from from a distance, peeping through an opening, and/or using techniques like binoculars, a mirror, camera, etc., and this stimulus becomes part of a masturbation fantasy during or after the observation.
When done openly it may or may not be appreciated, depending on the other person(s) being exhibitionistic.
Voyeurism is considered a deviant sexual act in most cultures, is most frequently practiced by males, and is tolerated to some degree in certain societies depending upon the circumstances (e.g., adolescent "Peeping Toms").
See also :