Islamism is an authoritarian political ideology that seeks to impose Islam on society. Thus, it is a form of theocracy. Whilst this definition is valid for the
imposition of any form of Islam on society, almost all Islamists adhere to ultra-conservative beliefs such as those of
Wahhabi Saudi Arabia.
The intellectual godfather of Islamism is Hassan al-Banna, who founded the Muslim Brotherhood. In effect, he transferred the fascist concept of the 'state' or 'super state' and imposed it upon the Islamic religion. This is why some describe Islamism as a form of Fascism. al-Banna was a known admirer of European Fascists such as Adolf Hitler and Benito Mussolini.
Jihadism is the use of violence to achieve Islamism.