higher-order vs intellectual

higher-order

adj
  • Involving more sophisticated thinking or reasoning. 

  • Of or relating to a class higher up in a hierarchy. 

intellectual

adj
  • Pertaining to, or performed by, the intellect; mental or cognitive. 

  • Relating to the understanding; treating of the mind. 

  • Suitable for exercising one's intellect; perceived by the intellect 

  • Endowed with intellect; having a keen sense of understanding; having the capacity for higher forms of knowledge or thought; characterized by intelligence or cleverness 

noun
  • An intelligent, learned person, especially one who discourses about learned matters. 

How often have the words higher-order and intellectual occurred in a corpus of books? (source: Google Ngram Viewer )