acquiescence vs imprimatur

acquiescence

noun
  • 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. 

  • 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. 

imprimatur

noun
  • Any mark of official approval. 

  • An official license to publish or print something, especially when censorship applies. 

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