invalid vs specious

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. 

specious

adj
  • Seemingly well-reasoned, plausible or true, but actually fallacious. 

  • Employing fallacious but deceptively plausible arguments; deceitful. 

  • Having an attractive appearance intended to generate a favorable response; deceptively attractive. 

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