2 Answers

fun·da·men·tal·ism (fnd-mntl-zm)
n.
1. A usually religious movement or point of view characterized by a return to fundamental principles, by rigid adherence to those principles, and often by intolerance of other views and opposition to secularism.
2.
a. often Fundamentalism An organized, militant Evangelical movement originating in the United States in the late 19th and early 20th century in opposition to Protestant Liberalism and secularism, insisting on the inerrancy of Scripture.
b. Adherence to the theology of this movement.

These are people that are so entrenched in their beliefs that they are totally inflexable and unable to appreciate the ideas or beliefs of others. Oh, and they want to foist those beliefs on everyone else.