The term "coon age" is a slang expression used to describe a long period of time. However, there are numerous synonyms that can be used to express the same idea. Some common ones include "donkey's years," "ages," "forever," "eternity," "a lifetime," "a century," "a millennium," "a coon's age," "an epoch," "aeon," "an era," and "time immemorial." Each of these phrases conveys the notion of a long, extended period of time that has passed or may be expected to pass. The choice of synonym largely depends on the writer's style and the context in which the expression is used.