happening vs inactivity

happening

noun
  • Something that happens. 

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

adj
  • Trendy, up-to-the-minute. 

  • Busy, lively; vibrant, dynamic; fashionable. 

inactivity

noun
  • The quality of being inactive; idleness; passiveness. 

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