smile vs sniggle

smile

verb
  • To express by smiling. 

  • To have (a smile) on one's face. 

  • To express amusement, pleasure, or love and kindness. 

  • To be propitious or favourable; to countenance. 

  • To look cheerful and joyous; to have an appearance suited to excite joy. 

noun
  • Favour; propitious regard. 

  • A facial expression comprised by flexing the muscles of both ends of one's mouth, often showing the front teeth, without vocalisation, and in humans is a common involuntary or voluntary expression of happiness, pleasure, amusement, goodwill, or anxiety. 

sniggle

verb
  • To chortle or chuckle; snicker. 

  • To ensnare. 

  • To fish for eels by thrusting a baited hook into their dens. 

  • To catch by this means. 

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