a gynorumus fart possesing nuclear like characterisitcs which spreads a toxic mushroom clowd of poo smog and a viscious nerve gass like odor across a large metropolitan area. Often resulting in a high number of lingering casualties among the population such as birth defects, cancer, tumors and other central nervous system disorders.
A huge toxic and long lingering fart generally audible but possesing a SBD like gasious cloud which lingers for many years similar to the devesation caused at the Chernobyl Nuclear Power in Russia
Ed: Did you hear about the huge fart Bob ripped in the office last week?

Eric: No what happened?

Ed: He had some serious fartosis and dropped a big one...it was like fartnobyl in the office. It was so bad that Marisa literally threw up at her desk because of it!
by threem January 29, 2010
Get the fartnobyl mug.