demountable vs dispensable

demountable

adj
  • Able to be removed from its mount; designed to be dismantled. 

noun
  • A temporary and portable building, especially a portable classroom in a school. 

dispensable

adj
  • Able to be done without; able to be expended; easily replaced. 

  • Subject to dispensation; possible to relax, exempt from, or annul. 

  • Capable of being dispensed; distributable. 

  • Not essential to be taken in as part of an organism's diet, as it can be synthesized de novo. 

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