hebetate vs lessen

hebetate

verb
  • To render obtuse; to dull; to blunt. 

adj
  • obtuse; dull 

  • Having a dull or blunt and soft point 

lessen

verb
  • To make less; to diminish; to reduce. 

  • To become less. 

conj
  • unless. 

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