When in doubt, ask for guidance. As an adjective or adverb, it is a musical term for loud and is pronounced FOR-tay. It is not a synonym for lucky or fortunate. It does not mean lavish or profuse. If one means militant or radical, then those words should be used.
Islamic radical is far more precise than Islamic fundamentalist.
Islamic scholar is far less loaded than Islamic fundamentalist when talking about someone who had dedicated himself to study of the religion. Devout Muslim is appropriate when talking about someone who takes his religion seriously. Gauntlet means a challenge, as in to throw down the gauntlet . Both are pronounced alike. This is only occasionally important in English.