melding vs weakening

melding

noun
  • A composite or hybrid, the result of being melded. 

weakening

noun
  • A structural principle of mathematical logic that states that the hypotheses of any derived fact may be freely extended with additional assumptions. 

  • An instance or process of loss of strength. 

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