authoritarianism vs rigidness

authoritarianism

noun
  • A form of government in which the governing body has absolute, or almost absolute, control. Typically this control is maintained by force, and little heed is paid to public opinion or the judicial system. 

rigidness

noun
  • Rigidity. 

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