invalid vs practical

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. 

practical

noun
  • A prop that has some degree of functionality, rather than being a mere imitation. 

  • A light fixture used for set lighting and seen in the frame of a shot as part of the scenery. 

  • A part of an exam or series of exams in which the candidate has to demonstrate their practical ability 

  • Laboratory experiment, test or investigation 

adj
  • Light fixtures used for set lighting and seen in the frame of a shot as part of the scenery. 

  • Being likely to be effective and applicable to a real situation; able to be put to use. 

  • Of a prop: having some degree of functionality, rather than being a mere imitation. 

  • Of a person, having skills or knowledge that are practical. 

  • Relating to, or based on, practice or action rather than theory or hypothesis. 

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