fixity vs unyieldingness

fixity

noun
  • The state or condition of being fixed. 

  • The position of an operator relative to its operand (prefix, postfix) or operands (infix). 

  • Something fixed. 

unyieldingness

noun
  • The state or condition of being unyielding. 

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