doc·tri·naire 
(dŏk′trə-nâr)
(dŏk′trə-nâr)adj.
Relating to, adhering to, or insisting upon a doctrine or theory without regard to practical considerations or problems.
n.
A doctrinaire person.
[French, from doctrine, doctrine, from Old French; see DOCTRINE.]
doc′tri·nairism n.
doc′tri·nari·an n.