reform vs weaken

reform

verb
  • To put into a new and improved form or condition; to restore to a former good state, or bring from bad to good; to change from worse to better 

  • To form again or in a new configuration. 

  • to reform a profligate man; to reform corrupt manners or morals; to reform a criminal 

  • To return to a good state; to amend or correct one's own character or habits 

noun
  • The change of something that is defective, broken, inefficient or otherwise negative, in order to correct or improve it 

weaken

verb
  • To make weaker or less strong. 

  • To become weaker or less strong. 

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