invalid vs valid

invalid

verb
  • To make invalid or affect with disease. 

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

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

  • Suffering from disability or illness. 

  • Intended for use by an invalid. 

valid

adj
  • Well grounded or justifiable, pertinent. 

  • Of an argument: whose conclusion is always true whenever its premises are true. 

  • Genuine - as distinguished from efficient or regular - sacrament. 

  • Related to the current topic, or presented within context, relevant. 

  • Of a formula or system: such that it evaluates to true regardless of the input values. 

  • Acceptable, proper or correct; in accordance with the rules. 

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