Fretrunner is to guitar what ricer is to cars.
A fretrunner tuns his amp louder than anyone else's, then proceeds to play some sloppy riffs. Most of the fretrunner's "technique" comes from effect pedals, but they still talk themselves up as if they didn't have on 3 types of delay. A fretrunner can only come down to earth if he is shown someone who can actually play the instrument.
Steve: He guys, you want to hear me rock???
Eric: No way, you just use delay you fretrunner!!!