Coon's age is a colloquial expression used to describe a very long period of time, often implying that it has been an excessively long time since the last occurrence of something. Antonyms for the term coon's age could be words like "recent," "current," "modern," and "contemporary." These words suggest a much shorter time frame or a sense of immediacy. Another set of antonyms could be "youth," "infancy," "adolescence," or "early days," as these words are associated with newness or freshness rather than antiquity. Together, these antonyms can provide a more nuanced understanding of time and emphasize the importance of living in the present.