ceaseless vs continuant

ceaseless

adj
  • Without stop or pause, incessant. 

  • Without an end. 

continuant

adj
  • Continuing; prolonged; sustained. 

noun
  • An endurant. 

  • A determinant formed from a tridiagonal matrix. 

  • A linguistic sound other than a stop. 

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