jefe vs slave-driver

jefe

noun
  • A boss in a business, company, or other organization. 

  • An officer with political influence; a head or chief in government, such as a sheriff, particularly where that person is Hispanic or of Mexican descent. 

slave-driver

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

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

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