disciplinarian[dis′ə pli ner′ē ən]
disciplinarian definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
a person who believes in or enforces strict discipline
disciplinarian definition by American Heritage Dictionary
One that enforces or believes in strict discipline.adjective