extremism – n. belief in and support for ideas that are very far from what most people consider correct or reasonable

background – n. the experiences, knowledge, education, etc., in a person’s past

off-track – expression away from the main point, thought, etc.; following a course of action that will lead to failure

isolated – adj. separate from others

behead – v. to cut off the head of (someone) especially as a punishment

(blood)shed – v. the killing of people especially in a war

Christianity – n. the religion that is based on the teachings of Jesus Christ

radicalize – v. to cause (someone or something) to become more radical especially in politics

Skype – v. to communicate on the internet using the program Skype

bipolar disorder – n. a mental illness in which a person experiences periods of strong excitement and happiness followed by periods of sadness and depression (also called “manic depression”)

challenge – v. to say or show that (something) may not be true, correct or legal