Introvert, a nontechnical psychological term referring to someone whose thoughts are generally turned inward. The term originated with the 20th century Swiss psychiatrist Carl Jung, who also coined the term extrovert. meaning someone who tends to direct their thoughts and actions outward, and who is more naturally sociable. An introvert tends more toward shyness and a focus on the inner processes than he or she does toward extroverted behavior. Jung believed that a well-balanced person possesses qualities of both the introvert and extrovert.