"favoring imposed order over freedom," 1862, from authority + -an. Compare authoritative, which originally had this meaning to itself. Noun in the sense of one advocating or practicing the principle of authority over individual freedom is from 1859.
an authoritarian regime
the timid child of authoritarian parents
author
authoress
authorial
authorisation
authorise
authoritarian
authoritarianism
authoritative
authority
authorization
authorize