self-willed vs strong-willed

self-willed

adj
  • Possessing self-will; determined to pursue one's own desires or adhere to one's own opinion.. 

  • Obstinate; strong-minded; unyielding to the desires, concern or opinions of others. 

  • He was so self-willed that he refused to do anything that did not grant instant satisfaction or direction. 

strong-willed

adj
  • Having a vigorous, independent will 

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