ganger vs slave-driver

ganger

noun
  • One who oversees a gang of workmen. 

  • One who is employed in conveying the coal through the gangways. 

  • One who or that which walks or goes; a goer; a walker. 

  • A horse that goes quickly. 

  • A length of chain, one end of which is fastened to an anchor when let go, when the other end is fastened to a hawser. 

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 ganger and slave-driver occurred in a corpus of books? (source: Google Ngram Viewer )