goad vs grumble at

goad

verb
  • To encourage or stimulate. 

  • To incite or provoke. 

  • To prod with a goad. 

noun
  • That which goads or incites; a stimulus. 

  • A long, pointed stick used to prod animals. 

grumble at

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