The phrase "prime of life" refers to an individual's period of maturity, typically in their middle years. Synonyms for this term include the "peak of life," which refers to the pinnacle of one's existence, where they have the most experience and knowledge. Another synonym is the "golden years," which represents a time of happiness, fulfillment, and prosperity. "Middle age" often implies a time of change, where people focus their attention on their careers and families while "midlife" emphasizes a phase of self-reflection and introspection. Other synonyms include "pinnacle," "prime," and "zenith" for expressing a person's peak period of life.