impalement vs pricking

impalement

noun
  • The act of torturing or executing someone by impaling them on a sharp stake. 

  • (obsolete) In the sense of an enclosure, the calyx of a flower. In still older works, also spelt empalement (q.v.) 

  • A space fenced in, such as by palings, possibly in the form of an enclosure or cup. 

  • The joining of two coats of arms on one shield. 

pricking

noun
  • The act of piercing or puncturing with a sharp point. 

  • The driving of a nail into a horse's foot so as to produce lameness. 

  • A sensation that pricks. 

  • A nicking. 

  • The mark or trace left by a hare's foot; a prick. 

  • The act of tracing a hare by its footmarks. 

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