The term "youthfulnesses" refers to the state or quality of possessing the characteristics of youth, such as vitality, energy, or freshness. Some synonyms that can be used in its place include "juvenescence," "adolescence," "youth," "freshness," "vigor," "liveliness," and "vitality." Additionally, terms like "exuberance," "zest," "sprightliness," and "pep" may be used to express the concept of youthful energy and enthusiasm. These synonyms can be used in various contexts, such as describing a person's appearance, demeanor, or personality. By employing different words to express the same idea, writers can add variety and interest to their language.