intelligent vs mentally stable

intelligent

adj
  • Having an environment-sensing automatically-invoked built-in computer capability. 

  • Characterized by thoughtful interaction. 

  • Having at least a similar level of brain power to humankind. 

  • Of high or especially quick cognitive capacity, bright. 

  • Well thought-out, well considered. 

mentally stable

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