Not knowing where to go, but just going. Not knowing what to do, but just doing it. When something out of the blue just happens and there is no other way to explain it. It is a way of life. Instead of wasting time on 'what ifs' and 'should've, could've' and would've' just do it.
Person 1: "Where we going?"
Person 2: "No Idea"
Person 1:"Spontanuous Moment"
Person 1:"Wow, can't believe we just saw a tornado go by"
Person 2:"So Spontanuous"
Noun: The state of getting buck nekkid without warning or forethought - often in a group setting, by choice and under the influence of alcohol. Derived from "nudity" and "spontaneity"
One minute we were all drinking, the next I was getting the red eye from Sean, the master of spontanudity.