lucent vs smouldering

lucent

adj
  • Emitting light; shining, luminous. 

  • Translucent; clear, lucid. 

smouldering

adj
  • Burning slowly, producing smoke but no flame. 

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

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