obstinate vs unvacillating

obstinate

adj
  • Not easily subdued or removed. 

  • Stubbornly adhering to an opinion, purpose, or course, usually with implied unreasonableness; persistent. 

  • Typical of an obstinate person; fixed and unmoving. 

unvacillating

adj
  • Not vacillating; firm, decided. 

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