The window of opportunity in which to talk to a person to whom you might be attracted, prior to when you have undressed them in your imagination and/or fantasized about them sexually. Usually between 10 seconds - 5 minutes after first sighting this person, depending on his or her attractiveness and your horniness.
(NOTE: Men andwomen of both gay and heterosexual persuasions are subject to the fleeting nudity zone).
Coined by the character Jeff on the British sitcom "Coupling."
"I would go over and say hi to Steve, but I've already imagined what it would be like to sit on his face, so the nudity buffer has been breached and it might be awkward."