precept vs watchword

precept

noun
  • A rule or principle, especially one governing personal conduct. 

  • An order issued by one local authority to another specifying the rate of tax to be charged on its behalf. 

  • A written command, especially a demand for payment. 

  • A rate or tax set by a precept. 

verb
  • To act as a preceptor; to teach a physician-in-training by supervising their clinical practice. 

watchword

noun
  • A word used as a motto, as expressive of a principle, belief, or rule of action; a rallying cry. 

  • A prearranged reply to the challenge of a sentry or a guard; a password or signal by which friends can be known from enemies. 

How often have the words precept and watchword occurred in a corpus of books? (source: Google Ngram Viewer )