equestrian vs gee-gee

equestrian

noun
  • One who rides a horse. 

  • Synonym of eques 

adj
  • Of or relating to the ancient Roman class of equites. 

  • Of horseback riding or horseback riders. 

gee-gee

noun
  • A horse. 

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