happening vs on the boil

happening

adj
  • Trendy, up-to-the-minute. 

  • Busy, lively; vibrant, dynamic; fashionable. 

noun
  • Something that happens. 

  • A spontaneous or improvised event, especially one that involves audience participation. 

on the boil

prep
  • About to happen; imminent. 

  • Playing exceptionally well. 

  • Going smoothly; working well. 

  • continuing; active; in a state of activity or development. 

  • simmering strongly and about to boil. 

  • boiling. 

  • (Of a player taking a pass) running at full speed towards the opposition. 

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