continuant vs unalterable

continuant

adj
  • Continuing; prolonged; sustained. 

noun
  • An endurant. 

  • A determinant formed from a tridiagonal matrix. 

  • A linguistic sound other than a stop. 

unalterable

adj
  • irrevocable or irreversible 

  • incapable of changing or being altered 

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