obtund vs sensitize

obtund

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

sensitize

verb
  • To render capable of being acted on by actinic rays of light. 

  • To make (someone) increasingly aware of, in a concerned or sensitive way. 

  • To make (someone or something) sensitive or responsive to certain stimuli. 

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