headstrong vs pertinacious

headstrong

adj
  • Determined to do as one pleases, and not as others want. 

pertinacious

adj
  • Holding tenaciously to an opinion or purpose. 

  • Stubbornly resolute or tenacious. 

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