aptness vs need

aptness

noun
  • suitability; the quality of being apt or suitable 

  • disposition of the mind; propensity 

  • speed or readiness in learning; docility 

  • proneness; tendency 

need

noun
  • A requirement for something; something needed. 

  • Lack of means of subsistence; poverty; indigence; destitution. 

verb
  • To be obliged or required (to do something). 

  • To be required; to be necessary. 

  • To want strongly; to feel that one must have something. 

  • To have an absolute requirement for. 

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