[woodruffw]

I think that's why they say "old-fashioned" instead of "has an extremely old (attestable) etymology."

As a native English speaker, "poppycock" sounds more "old-fashioned" (maybe "quainter") than "snail," even though "snail" might actually be older.

[thaumasiotes]

Well, it's pretty easy to assume that snail is very, very old. As I said above, in my opinion it doesn't sound "old-fashioned" because it's still current, and how old it might be is irrelevant.

But see also my observation about the English female names Gertrude and Etheldreda. Which one is more old-fashioned?