facile vs shallow

facile

adj
  • Effortless, fluent (of work, abilities etc.). 

  • Easy, now especially in a disparaging sense; contemptibly easy. 

  • Lazy, simplistic (especially of explanations, discussions etc.). 

  • Of a reaction or other process, taking place readily. 

shallow

adj
  • Not intellectually deep; not penetrating deeply; simple; not wise or knowing. 

  • Not steep; close to horizontal. 

  • Not far forward, close to the net. 

  • Having little depth; significantly less deep than wide. 

  • Concerned mainly with superficial matters. 

  • Extending not far downward. 

  • Lacking interest or substance. 

verb
  • To make or become less deep. 

noun
  • A costermonger's barrow. 

  • A shallow portion of an otherwise deep body of water. 

  • A fish, the rudd. 

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