Basicly refers to the action of gaining information about a pre-targeted object, it being a person, place, thing or action. One of the ways to do RV is the Ganzfeld where all senses are supressed at their best in order for it be easy to the mind to focus on something outside of the body's reach.
The persons body is usualy "blocked" by some kind of barrier(ex: time, place) that doesnt allow him/her to gain information through any physical method (sight, touch). Thus RV being the act of gaining information of an object through a method diferent of the physical ones.
Also see: psi (_NOT_ pounds per square inch)
Johny RV'd his friends room and found out that Billie was touching himself.
In everday use, an RV would be someone that looks ugly, shabby, or generally not good . Or it could be someone constantly followed by an RS.
See also: RS
"That RV is being followed by his RS"
"What a bunch of RV's"
That bitch was NASTY, I could smell her R.V.S. from 40 ft. away--across the platform!
You've probably heard of people going RV'ing, which is the act of traveling in a motorhome or trailer.