invalid vs legitimate

invalid

adj
  • Not valid; not true, correct, acceptable or appropriate. 

  • Suffering from disability or illness. 

  • Intended for use by an invalid. 

verb
  • To make invalid or affect with disease. 

  • To exempt from (often military) duty because of injury or ill health. 

legitimate

adj
  • In accordance with the law or established legal forms and requirements. 

  • Lawfully begotten, i.e., born to a legally married couple. 

  • Authentic, real, genuine. 

  • Relating to hereditary rights. 

  • Belonging or relating to the legitimate theater. 

  • Conforming to known principles, or established or accepted rules or standards; valid. 

verb
  • To make legitimate, lawful, or valid; especially, to put in the position or state of a legitimate person before the law, by legal means. 

noun
  • A person born to a legally married couple. 

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