coalition vs weakening

coalition

noun
  • A temporary group or union of organizations, usually formed for a particular advantage. 

  • The collective noun for a group of cheetahs. 

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 coalition and weakening occurred in a corpus of books? (source: Google Ngram Viewer )