mandatory vs significant

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. 

significant

adj
  • Signifying something; carrying meaning. 

  • Reasonably large in number or amount. 

  • Having a low probability of occurring by chance (for example, having high correlation and thus likely to be related). 

  • Having a covert or hidden meaning. 

  • Having a noticeable or major effect. 

noun
  • That which has significance; a sign; a token; a symbol. 

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