benumb vs obtund

benumb

verb
  • To deaden, dull (the mind, faculties, etc.). 

  • To make numb, as by cold or anesthetic. 

obtund

verb
  • To reduce the edge or effects of; to mitigate; to dull. 

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