I tend to think the "eternal" Virtues of the
In my view, I would expect Epicurus to have been suspicious of anything claiming to be "eternal" by nature, since it's core physics that only the atoms have that attribute, and it appears that the gods only have it "by virtue" of their being able to replace their atoms over time without a time limit. So calling something "imperishable" would fit for the gods and be an allusion to god-like status, but would be allegorical in every other case, especially in terms of "values" or attitudes generated by humans.
And in those definitions Kalosyni cited my understanding of the latin is that "virtus" has a strong implication of "strength" as its core meaning, thus being associated with "men," and so "strength" can refer to any number of things that are effective toward a goal and wouldn't carry any unchanging moral meaning.
Given his view of the nature of the universe I would expect Epicurus' to have rejected the whole idea of morality being unchanging or eternal (meaning virtue with a definition that doesn't change over time, place, or person). The only thing given us by nature is the faculty of pleasure and pain and that seems to me to be almost completely dependent on context. Yes the human body reacts in certain ways to fire, for instance, so at some point fire applied directly to the skin is always going to be painful, but human interactions don't have that same kind of physical inevitability. Humans have "free will" and don't always react the same way.