moralist

noun

1. (derogatory)One who bases all decisions on perceived morals, especially one who enforces them with censorship.
2. A teacher of morals; a person who studies morality; a moral philosopher.

   “What must the old man have felt as, in ghastly terrifying solitude, by the light of one lamp feebly illuminating a little space of gloom, he in a few brief lines daubed the history of his nation's death upon the cavern wall? What a subject for the moralist, or the painter, or indeed for any one who can think!”