gnawing vs smouldering

gnawing

noun
  • The process by which something is gnawed. 

  • A sensation of being gnawed. 

adj
  • severe or intense 

smouldering

noun
  • The act by which something smoulders; residual heat. 

adj
  • Burning slowly, producing smoke but no flame. 

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