The word "adultnesses" is not very common in the English language, and there are not many commonly used synonyms for it. However, some possible alternatives include "maturity," "adulthood," "grown-upness," "responsibility," and "sobriety." These terms all have different connotations and shades of meaning, but they generally refer to the traits and behaviors associated with being a fully developed and responsible member of society. Whether it's making important decisions, taking care of oneself and others, or acting with dignity and integrity, the concept of "adultness" is an essential part of our social and cultural norms.