continuant vs unvarying

continuant

adj
  • Continuing; prolonged; sustained. 

noun
  • An endurant. 

  • A determinant formed from a tridiagonal matrix. 

  • A linguistic sound other than a stop. 

unvarying

adj
  • persistent, constant, changeless 

  • lacking variety; having a uniform character 

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