Is there a word for those?

Ever hear a word that basically defines itself? Here's an example: My daughter likes to say "over-exaggerate". Which is pretty much in itself an example of whatever she's describing, because exaggeration is already overdoing the description of something. Does that make sense? It's like the opposite of an oxymoron (not to be confused with an oximoron--that guy who sells Oxiclean), where the term's name is an impossibility.

So now I'm wondering if anybody has a term for these, or examples like "overexaggerate"?

Piper Denna

Romance is sexy!