Fundamentalist

A deep and totalistic commitment to a belief in the infallibility and inerrancy of holy scriptures, absolute religious authority, and strict adherence to a set of basic principles (fundamentals), away from doctrinal compromises with modern social and political life.

Within Christianity, this term has been used since the 1920's to refer to the most religiously conservative group within Protestant Christianity. Within Judaism, Islam and other religions, the term is used to refer to the extreme conservative wing that has emerged as a response to the fear that modernity will erode or even eradicate their faith and morality.