airtight vs demonstrative

airtight

adj
  • Highly reserved in some matter, particularly tight-lipped or tight-fisted. 

  • Having no weak points or flaws. 

  • Impermeable to air or other gases. 

demonstrative

adj
  • given to open displays of emotion 

  • that specifies the thing or person referred to 

  • that serves to demonstrate, show or prove 

noun
  • A demonstrative pronoun. 

  • A demonstrative adjective. 

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