The term
political radicalism (or simply, in
political science,
radicalism) denotes
political principles focused on
altering social structures through revolutionary means and changing
value systems in fundamental ways. Derived from the Latin
radix (root), the denotation of radical has changed since its eighteenth-century coinage to comprehend the entire political spectrum—yet retains the "change at the root" connotation fundamental to
revolutionary societal change. Historically,
radicalism has referred exclusively to the radical left (under the single category of
far-left politics) and rarely incorporating
far-right politics, though these may have revolutionary elements; the prominent exception is in the
United States where some consider radicalism to include both political extremes of the radical left and the
radical right. In traditional labels of the spectrum of political thought, the opposite of radical on the "right" of the political spectrum is termed
reactionary.