glower vs grin

glower

verb
  • To look or stare with anger. 

noun
  • An angry glare or stare. 

  • That which glows or emits light. 

grin

verb
  • To grin as part of producing a particular facial expression, such as a smile or sneer. 

  • To express by grinning. 

  • To smile, parting the lips so as to show the teeth. 

noun
  • A smile in which the lips are parted to reveal the teeth. 

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