Parrhesia is a Greek word that translates very roughly as free speech. A parrhesiates (one who makes is use of parrhesia) is one who is willing to speak the truth regardless of the folkways, mores, or even laws of the society, and regardless of personal risk. The parrhesiates chooses a moral duty to the truth over his own self-interest and well being. Socrates was the archetypical parrhesiastes, as his methods were discomfitting to those he spoke to, and in the end he was killed for his adherence to this philosophy.
Parrhesia has in recent years come to be important to the postmodernism movement. Michel Foucault once gave a series of lectures at Berkeley entitled "Discourse and Truth: The Problematization of Parrhesia." Since the postmodernist movement holds that the truth is not absolute, but is instead subjective, the postmodern parrhesiates is motivated by his/her convictions about the issues in question, and the desire to expose all angles of any given issue. These people are often very vocal and blunt in their criticism of hierarchical structures of power. Since postmodernism holds that there is no universal truth, their philosophy runs directly counter to organizations that are based around ideologies, such as Communism, Democracy, Christianity, Science, Progress, etc. Since all ideology have their fallacies and hypocrisies, postmodern authors often have ample material for criticism. This has led to postmodernist authors being derided as smut artists by the powers in question, and in some cases, even persecuted (Salman Rushdie, for example, has received death threats in certain Muslim countries over his book, "The Satanic Verses."