acquiescence vs endorsement

acquiescence

noun
  • Inaction, passivity, or neglect to take legal action when it is called for in order to assert, preserve, or safeguard a right, and which inaction implies the abandonment of said right. 

  • A silent or passive assent or submission, or a submission with apparent content, distinguished from avowed consent on the one hand, and on the other, from opposition or open discontent; quiet satisfaction. 

endorsement

noun
  • The act or quality of endorsing 

  • Sponsorship, in means of money, by a company, business or enterprise. 

  • An amendment or annotation to an insurance contract or other official document (such as a driving licence). 

  • An instructor's signed acknowledgement of time practising specific flying skills. 

  • Permission to carry out a specific skill or application in a field in which the practitioner already has a general licence. 

  • Support from an important, renowned figure of a media (celebrity, politics, sports, etc.), to get back up. 

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