There are a plethora of synonyms for the phrase "adult life". Some of the most common synonyms include "adulthood", "maturity", "grown-up years", "post-adolescent years", and "full-fledged life". Each of these synonyms puts an emphasis on the idea that the individual has reached a level of responsibility and independence commonly associated with an adult. Another synonym that could be used is "seniority", which indicates that the person has a certain level of wisdom and experience in their life. Regardless of the synonym used, each one serves as a reminder that there is a time in every person's life when they move from being a child to a fully-fledged adult.