1) Radicalism 
• (n.) The principles of the Jacobins; violent and factious opposition to legitimate government.
Jac'o·bin·ism noun [ Confer French Jacobinisme .] The principles of the Jacobins; violent and factious opposition to legitimate government. « Under this new stimulus, Burn's previous Jacobitism passed towards the opposite, but not very distant, extreme of Jacobinism .» J....
Jacobinism, as a belief in a nationally uniform and centralised government, hostile to the division of parcellization of sovereignty remains in current political usage, especially in France. Robespierre's Jacobins established a revolutionary dictatorship when France was at war with and encircled by the reactionary European powers. Their conduct of ...
[n] - the ideology of the most radical element of the French Revolution that instituted the Reign of Terror
noun the ideology of the most radical element of the French Revolution that instituted the Reign of Terror
Political philosophy of the leaders of the French revolutionary government. After reaching power in the revolutionary dictatorship of 1793, the Jacobins set about safeguarding the values of the revolution and public virtue by a Reign of Terror against opposing views.