continuant vs relentless

continuant

adj
  • Continuing; prolonged; sustained. 

noun
  • An endurant. 

  • A determinant formed from a tridiagonal matrix. 

  • A linguistic sound other than a stop. 

relentless

adj
  • Unremitting, steady and persistent. 

  • Unrelenting or unyielding in severity. 

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