"Ages on end" is a phrase used to describe something that lasts a very long time, often to the point of being tedious or boring. There are several synonyms that can be used to convey the same meaning, including "eternity," "an eternity," "forever," "endlessly," and "indefinitely." Other similar phrases include "for good measure," "time without end," "beyond measure," and "time immemorial." These phrases all convey the idea of something being endless, without end or limit. Whether used in fiction, poetry, or everyday conversation, these synonyms for "ages on end" all pack a powerful punch when you need to describe something that seems to go on forever.