smouldering vs sultry

smouldering

adj
  • Burning slowly, producing smoke but no flame. 

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

sultry

adj
  • Very hot and dry; torrid. 

  • Hot and humid. 

  • Sexually enthralling. 

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