du'a' vs imprecation

du'a'

noun
  • private prayer by an individual 

imprecation

noun
  • The act of imprecating, or invoking evil upon someone; a prayer that a curse or calamity may befall someone. 

  • A curse. 

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