provocation vs softening

provocation

noun
  • The second step in OPQRST regarding the investigation of what makes the symptoms MOI or NOI improve or deteriorate. 

  • The act of provoking, inciting or annoying someone into doing something 

  • Something that provokes; a provocative act 

softening

noun
  • The process of becoming soft. 

  • The process of making something soft. 

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