clean as a hound's tooth vs rustic

clean as a hound's tooth

adj
  • Very clean; very innocent. 

rustic

adj
  • Simple; artless; unaffected. 

  • Country-styled or pastoral; rural. 

  • Crude, rough. 

  • Unfinished or roughly finished. 

noun
  • A noctuoid moth. 

  • Any of various nymphalid butterflies having brown and orange wings, especially Cupha erymanthis. 

  • A (sometimes unsophisticated) person from a rural area. 

How often have the words clean as a hound's tooth and rustic occurred in a corpus of books? (source: Google Ngram Viewer )