A combination of the words "fuck" and "shit". Usually used to express deep anger when one is pissed off to the max. Can also be used to describe an object as great, like one would say something is "the shit".
"Brad, I was driving your sister home, but we were in a terrible crash, and... I'm so sorry..."
"Hey, remember those Harvest Moon games we used to play?"
"Yeah man, those games were the fuckandshit."