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 19, 2005
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
by Gilbert Godfrey December 08, 2004
by Courtster May 03, 2008
by Shady Toni December 13, 2008
Ghetto ass on a white girl!
by Brooke January 21, 2004
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 08, 2010