a person who tries to apply some doctrine or theory without sufficient regard for practical considerations; an impractical theorist.

dogmatic about others' acceptance of one's ideas; fanatical

a doctrinaire preacher.

merely theoretical; impractical.

of, pertaining to, or characteristic of a doctrinaire.

adjective

amenable , flexible , manageable , obedient , submissive

adjective

authoritarian , authoritative , biased , bigoted , bullheaded * , dictative , dictatorial , dogged , fanatical , impractical , inflexible , insistent , magisterial , mulish , obstinate , one-sided , pertinacious , pigheaded * , rigid , speculative , stiff-necked * , stubborn , unrealistic , dogmatic