A modified form of "fantastic" that injects the word "ass" to reverse the meaning. Asstastic refers to something that sucks or is of poor quality.
by HugeBreasticle March 18, 2005
 Get the Asstasticmug.
Get the Asstasticmug. A word used to describe a girl with such a breathtaking, beautiful booty that it becomes that girls defining factor.
by Dr fantastic September 11, 2014
 Get the Asstasticmug.
Get the Asstasticmug. by Gilbert Godfrey December 8, 2004
 Get the asstastemug.
Get the asstastemug. by Courtster May 3, 2008
 Get the Asstasticmug.
Get the Asstasticmug. by Shady Toni December 19, 2008
 Get the Asstasticmug.
Get the Asstasticmug.  Get the Asstasticmug.
Get the Asstasticmug. When a guy/girl has a glorious backside to the point it makes you stop whatever you are doing just to watch it sway away
I was walking through the mall when through my peripheral I spotted this asstastic chick swaying away and wads mesmerized into a coma!
by Nomolos69 September 7, 2010
 Get the Asstasticmug.
Get the Asstasticmug.