diffident vs viscerotonic

diffident

adj
  • Lacking self-confidence; timid; modest 

viscerotonic

adj
  • Designating a personality type characterised as sociable, easy-going, and comfort-seeking. 

noun
  • A person with such a personality. 

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