Someone who insists on something.

Roget 739: severity; strictness, harshness etc. adj.; rigor, stringency, austerity; inclemency etc. (pitilessness) 914.1; arrogance etc. 885; precisianism^†.    arbitrary power; absolutism, despotism; dictatorship, autocracy, tyranny, domineering, oppression; assumption, usurpation; inquisition, reign of terror, martial law; iron heel, iron rule, iron hand, iron sway; tight grasp; brute force, brute strength; coercion etc. 744; strong hand, tight hand.    hard lines, hard measure; tender mercies [Iron.]; sharp practice; pipe-clay, officialism.    tyrant, disciplinarian, precisian^†, martinet, stickler, bashaw^†, despot, hard master, Draco, oppressor, inquisitor, extortioner, harpy, vulture; accipitres^†, birds of prey, raptorials^†, raptors^†.    ... show more

Roget 606: obstinateness etc. adj.; obstinacy, tenacity; cussedness [U.S.]; perseverance etc. 604.1; immovability; old school; inflexibility etc. (hardness) 323; obduracy, obduration^†; dogged resolution; resolution etc. 604; ruling passion; blind side.    self-will, contumacy, perversity; pervicacy^†, pervicacity^†; indocility^†.    bigotry, intolerance, dogmatism; opiniatry^†, opiniativeness; fixed idea etc. (prejudgment) 481; fanaticism, zealotry, infatuation, monomania; opinionatedness opinionativeness^†.    mule; opinionist^†, opinionatist^†, opiniator^†, opinator^†; stickler, dogmatist; bigot; zealot, enthusiast, fanatic.    ... show more

Dutch: voorstander, ijveraar