doctrinaire (n.) Look up doctrinaire at Dictionary.com
1820, from Fr. doctrinaire (14c.), from L. doctrina (see doctrine). At first used in the context of Fr. politics, contemptuously applied by rival factions to those who tried to reconcile liberty with royal authority after 1815. Hence, anyone who applies doctrine without making allowance for practical considerations (1831). As an adjective, from 1834.