Guide to Understanding terrorism for Teachers and Students. "Islam forbids all forms of terrorist activity. There are however some extreme factions of people who, in the name of Islam, terrorise both Muslims and non-Muslims alike. The most well-known of these militant groups are al-Qaeda and ISIS in Syria and Iraq. These terrorist groups are called Khawarij in Islamic terminology because the term refers to those who rebel against Islam and the Muslims." By Abu Khadeejah Abdul-Wahid. Download original PDF.