invalid vs shaky

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. 

shaky

adj
  • Wavering; undecided. 

  • Easily shaken; tottering; unsound. 

  • Shaking or trembling. 

  • Full of shakes or cracks; cracked. 

  • Nervous, anxious. 

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