early 14c., of the order of Dominican friars whose order built its first convent near the church of Saint-Jacques in Paris, from Old French Jacobin (13c.) "Dominican friar," also, in the Middle East, "a Copt;" see Jacob. The Revolutionary extremists took up quarters there October 1789. Used generically of radicals and allegedly radical reformers since 1793. Related: Jacobinism.
An extreme radical party during the French Revolution named for the place where its founders first met, a convent of Jacobin friars. It was led by Robespierre.
Note: In general, a member of an extremist or radical group is often called a “Jacobin.”