What are synonyms for introversion?

Shy, demure, quiet, deep, shy, depressed, gentle.

Psychology refers to a kind of directionality in temperament. People's words, thoughts and emotions often point inward, indicating that the excitement process of the nervous system is dominant. Eysenck Personality Questionnaire describes the typical introverted personality as quiet, extroverted, introspective, and likes to be alone without contact with others. Be conservative and keep a certain distance from others (unless you are a close friend). Tend to do things in a planned way, look ahead and look back, not impulsive.