precisian

noun

1. A religious purist; a Puritan.
2. Someone who strictly observes the rules; a pedant or stickler.

   “Her speech was hardly more grating upon him, precisian though he was, than the careless, untutored lapses of a child might have been; all the senses of comparison as readily ignored them.”

   ““A sister of mine will be there,” explained the one, knowing the Duke to be a precisian.”