diffident vs extroverted

diffident

adj
  • Lacking self-confidence; timid; modest 

extroverted

adj
  • Synonym of inside-out. 

  • Turned or thrust outwards, especially 

  • Of or characteristic of the personality of an extrovert: outgoing, sociable. 

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