notional vs substantial

notional

adj
  • Of, containing, or being a notion; mental or imaginary. 

  • Having descriptive value as opposed to a syntactic category. 

  • Used to indicate an estimate or a reference amount 

  • Full of ideas or imaginings. 

  • Speculative, theoretical, not the result of research. 

noun
  • A fake company used as a front in espionage. 

substantial

adj
  • Not imaginary; real; actual; true; veritable. 

  • Most important; essential. 

  • Having a substance; actually existing. 

  • Corporeal; material; firm. 

  • Possessed of goods or an estate; moderately wealthy. 

  • Satisfying; having sufficient substance to be nourishing or filling. 

  • Large in size, quantity, or value; ample; significant. 

  • Having good substance; strong; stout; solid; firm. 

noun
  • Anything having substance; an essential part. 

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