I've known skeuomorph since 1966, though it didn't get into Chambers until about the 7th Edition, and means a decorative feature which mimics a functional feature found in older forms of a tool, building etc using a different material.

Kakistocracy is government by the worst, and has been in the dictionary for as long as I can remember.

The post-turtle turnes up in Ben Macintyre's column on language in yesterday's Times, and apparently comes from a 75 year old Texan who explained: "When you're driving down a country road and you come across a fence post with a fence post with a turtle balanced on top, that's a post-turtle. You know she didn't get up there by herself, she doesn't belong up there, she doesn't know what to do while she is up there, and you just wonder what kind of dumb ass put her up there to begin with".