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2.
Gettting naked at weird or random times or places
"...and I was watching a disney movie wit my baby cousin and all of a sudden it was like DAMN, spontinudity....Snow Whites a freak, thats all I can say..."
by LilMerm October 31, 2003
 
1.
Unplanned and impulsive removal of all clothing.
Spontinudity was rampant at the frat party last night.
by Sorority Mom July 21, 2009