opinion vs reflection

opinion

noun
  • The formal decision, or expression of views, of a judge, an umpire, a doctor, or other party officially called upon to consider and decide upon a matter or point submitted. 

  • A belief, judgment or perspective that a person has formed, either through objective or subjective reasoning, about a topic, issue, person or thing. 

  • a judicial opinion delivered by an Advocate General to the European Court of Justice where he or she proposes a legal solution to the cases for which the court is responsible 

  • The judgment or sentiment which the mind forms of persons or things; estimation. 

reflection

noun
  • Careful thought or consideration. 

  • The act of reflecting or the state of being reflected. 

  • The process or mechanism of determining the capabilities of an object at run-time. 

  • The folding of a part; a fold. 

  • Something, such as an image, that is reflected. 

  • The property of a propagated wave being thrown back from a surface (such as a mirror). 

  • An implied criticism. 

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