Portmanteau of the words Awkward and Atrocity, so means a very embarrassing event. Could be embarrassing enough to give one PTSD. Could also be Atroward...
A turd so unspeakably vile that the very act of committing it may be, under certain conditions, deemed a War Crime by the U.N.
Main characteristics of an arsetrocity include extensive skidmarks, a hanging and unbearable smell that takes long time to go away, extreme pebble-dashing and giving the bathroom the general air of the aftermath of a Nuclear/Biological/Chemical attack
"Man, I'd stay outta the bathroom for a while, I just committed an Arsetrocity" declared Paul, after he'd graced the shitter with his presence following a heavy night on the Guinness skidmarks pebbledash Guinness} poop stink
This term is similar to the apostrophe catastrophe, but it is reserved for the most revolting of apostrophe errors. Only a true abomination of a linguist would commit an apostrophe atrocity.