Posted a little while back:

Is there a -nym for words that are a different word when read backwards, like "dog" and "god," or "pot" and "top"?

There was an answer but it didn't mention ananym, which is the only word I know for this. In preparing to post this, I researched it and found it's a very obscure word, so probably a recent invention.

It seems to have a specific meaning of a reversed name adopted as a pseudonym.