activity vs occurrent

activity

noun
  • Something done as an action or a movement. 

  • The lexical aspect (aktionsart) of verbs or predicates that change over time and have no natural end point. 

  • Something done for pleasure or entertainment, especially one involving movement or an excursion. 

  • The state or quality of being active; activeness. 

  • The number of radioactive decays per unit time. Unit for it: becquerel or curie 

  • The propery of substances to react with other substances 

occurrent

noun
  • An event, something that occurs. 

  • One who comes to meet another. 

adj
  • Pertaining to occurrence; having to do with an occurrence. 

  • Current, actual, occurring. 

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