A Censor was a title held by certain officers within the Romulan Star Empire.
This position, along with that of Tribune, were part of the Offices Imperium and consisted of officers within the Romulan Star Navy. These Romulans held a rank that made them the equal of a Subcommander with their leadership role involving coordinating operations between the various branches. They were often required to organize multi-year missions which brought about a high degree of respect from their subordinates.
These special ranks were positions that were respected not because of their direct command abilities but rather because of their other skills which were a great value to the empire. As such, many censors along with Legate's had never commanded a starship. (Last Unicorn RPG module: The Way of D'era: The Romulan Star Empire)