A radical is a person subscribing to a political ideology supporting massive, unmeasured, and rapid change. Radicalism is contrasted with conservatism that advocate minimum change, reactionary action advocating counter-change, as well as progressivism advocating moderate/measured change.
A radical would want to chang, for example, a feudal system into a completely capitalist system, or a completely capitalist system into a communist one. Another exaple of radicalism would be a person who wanted to change an Islamic Theocracy into an Atheist state (see en.wikipedia.org/wiki/state_atheism)!
Radical (rahd eek al) is a word used proficiently and often by Michaelangelo of the Teenage Mutant Ninja Turtles. He is the only one on earth that truly knows its awesomeness, although such scholars as WilliamPreston-Esquire and Theordore Theordore Logan have come close to unveiling the true natures of such speak. The best reason for dividing radical is to make more mini-radicals influence from the beinning radical, in hopes of creating a little radical for everyone. And pizza.