heat of passion vs provocation

heat of passion

noun
  • An outburst of anger that leads one to commit a criminal act, and is itself influenced by preceding events that might cause a reasonable person to lose self control. 

provocation

noun
  • Something that provokes; a provocative act 

  • 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 

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