Extremist noun – A person who favors rapid and sweeping changes especially in laws and methods of government. Adherent and extremist are semantically related. Sometimes you can use "Adherent" instead a noun "Extremist". Nearby Words: extreme, extremity, extremism, extremal
Such darker utilitarianism can also be a motivation behind a Well-Intentioned Extremist, although a Well-Intentioned Extremist may just as easily be a darker form of deontologist or an adherent to some other ethical philosophy.
The Master from Fallout 1 was very much an adherent of Evilutionary tenets in the Well-Intentioned Extremist mould (certainly, the backdrop of a post-nuclear apocalypse lent his reasoning some gravitas).