dispensable vs mandatory

dispensable

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

  • Capable of being dispensed; distributable. 

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

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

mandatory

adj
  • Of, being or relating to a mandate. 

  • Obligatory; required or commanded by authority. 

noun
  • A sign or line that require the path of the disc to be above, below or to one side of it. 

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