boff vs onfall

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. 

onfall

verb
  • To assault, attack. 

  • To fall on or upon. 

noun
  • The fall of the evening. 

  • A fall of rain or snow. 

  • A falling on or upon; an attack, onset, or assault. 

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