governor vs slave-driver

governor

noun
  • Boss; employer; gaffer. 

  • A constituent of a phrase that governs another. 

  • A device which regulates or controls some action of a machine through automatic feedback. 

  • A member of a decision-making for an organization or entity (including some public agencies) similar to or equivalent to a board of directors (used especially for banks); a member of the board of governors. 

  • A pilot; a steersman. 

  • Father. 

  • The chief executive officer of a first-level division of a country. 

slave-driver

noun
  • An employer who demands excessive amounts of work from employees. 

  • An overseer of slaves at work; a person who puts slaves to work. 

How often have the words governor and slave-driver occurred in a corpus of books? (source: Google Ngram Viewer )