The term heretic comes from the Old French word eretique traced back to the 14th century and haereticus in Latin. Hairetikos, in Greek etymology means "able to choose" and the adjective form is hairein or heresy.
In religion, specifically the Christian and Catholic Church, heresy are beliefs of a member of the church which contradict their core principles.
A heretic is someone who has their own religious ideas and opinions which go against those that are accepted by his or her church. The prefix "here" meaning stick and the suffix "ic" meaning the study or knowledge of. Heretics have their own ideas that are contrary to the doctrines set by that church; they are misbelievers, pagans, and irreligious.
A heretic is different from an apostate, which is someone who decides to completely abandon their religion and is no longer considered a member of that Church. In contrast, a heretic still considers themselves as part of their Church and even more so, they actually think they are the true believer. Obviously, this created extreme doctrinal controversy within that religious community.
During the medieval times, the church used military tactics and legal campaigns to try and minimize and diminish heresy. The most common way of dealing with heretics or small groups of heretical individuals would be excommunication. This is the process of formally ostracizing people from the religious body. Within the Christian and Catholic Churches, they will maintain a spiritual separation from the heretics and they are officially excluded from their religious societies.
As a modern day example, Carlton Pearson was considered to be a religious megastar. He prayed at the Bush Sr. White House, hosted his own television show, and flew all over the world giving lectures at religious gatherings. However, Pearson got caught in a scandal which branded him as a heretic; he stopped believing in Hell. People began to turn against him because all of a sudden, they were being told that the premise of their faith was wrong. Following his changed opinion of the after life, Pearson was essentially shunned from the Christian community. People take serious offence to the issue and there are many recorded cases of heresy trials being held. A chemistry teacher was on trial for heresy in 1995 for teaching evolution. Another minister was tried for performing gay marriage and some are actually stripped of their preaching credentials.
Heretics are not respected members of their religious communities. They are often disliked and disregarded for having beliefs that go against their Church's beliefs.
The Bible states: "But false prophets also arose among the people, just as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Master who brought them, brining upon themselves swift destruction" (2 Peter 2:1).
"26 Bible Verses Abou Heresy." What Does the Bible Say About Heresy? Good News Publishers, n.d. Web. 21 Nov. 2012. <http://www.openbible.info/topics/heresy>.
"heretic, n. and adj.". OED Online. September 2012. Oxford University Press. 21 November 2012 <http://www.oed.com/view/Entry/86197?redirectedFrom=heretic&>.