There are many synonyms for the term "grown up" which can be used to describe a person who has reached adulthood or maturity. Some of the most common synonyms include adult, mature, elderly, senior, seasoned, accomplished, and experienced. Other synonyms include developed, evolved, progressed, sophisticated, refined, and cultured. Each of these synonyms carries its own connotation and can be used to describe different aspects of a person's personality or character. For example, "accomplished" and "experienced" suggest a person who has achieved a high level of success in their career or personal life, while "sophisticated" and "refined" imply a person with refined taste and an appreciation for culture and the finer things in life.