boff vs thwack

boff

verb
  • To hit; to strike. 

  • to have sexual intercourse (with someone) 

noun
  • A great success; a hit. 

  • A pupil who works hard; a swot. 

  • A line in a film etc that elicits such a laugh. 

  • A big laugh. 

  • A hit or smack. 

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 boff and thwack occurred in a corpus of books? (source: Google Ngram Viewer )