adj. A word that I and probably many other people in this world made up without a reason. Used with sarcasm, defining something that isn't fantastic but hell with it. =]
FUCKtastic is like fantastic but so much better.
its when you are so happy, instead of saying fucking fantastic, you just say FUCKtastic.
You can even say it when you have an orgasm, or better, a RAWRgasm :)
1: Holy shit!! he just got hit by a car!
2: HAH!! Thats FUCKtastic!!!!!
or
1:RAWR!!! give it to me!!! i want a RAWRgasm!!!
2: AHH!!! thats FUCKtastic!!!