noun.
One who theorizes without a sufficient regard to practical considerations; a political theorist; an ideologist; one who undertakes to explain things by one narrow theory or group of theories, leaving out of view all other forces at work.
noun.
In French history, during the period of the Restoration (1815-30) and later, one of a class of politicians and political philosophers who desired a constitution constructed on historical principles, especially after the analogy of the British constitution.
Characteristic of a doctrinaire or unpractical theorist; merely theoretical; insisting upon the exclusive importance of a one-sided theory.