burp vs thwack

burp

verb
  • To utter by burping 

  • To cause someone (such as a baby) to burp. 

  • To open (a container of fermenting substance) to allow the release of accumulated gas. 

  • To emit a burp. 

noun
  • A belch. 

thwack

verb
  • To beat. 

  • To hit with a flat implement. 

  • To fill to overflow. 

noun
  • The act of thwacking; a strike or blow, especially with a flat implement. 

  • A heavy slapping sound. 

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