A concept closely related with palindromes is the semordnilap.
Notice that it's palindrome, reversed? While a palindrome is identical either way, a semordnilap spells another meaningful but different text when reversed.
REPAID / DIAPER
STRESSED / DESSERTS
GATEMAN / NAMETAG
This term is apparently a new coinage as my Chambers 2000 doesn't list it, but it gets plenty of hits on the web.
So, a whole reversal clue is based on a semordnilap. Here's a nice recent one:
Guardian 24672 (Rufus): Retired don is still in bed (3, 2)
The answer is NOT UP, the reverse of PUT ON.
I've talked about reversal clues in detail here: the Reversal Clue Type.
- Some semordnilaps are not coincidental, the term yob was reputedly coined specifically as a reverse spelling of the word boy.
- The reverse spelling of Mr. Mxyzptlk has a powerful role to play in Superman comics. If the supervillain said or spelled Kltpzyxm (i.e. his name backwards), he was involuntarily sent back to the fifth dimension for at least 90 days. Superman should be glad the supervillain did not have a palindromic name.
- The magic Mirror Of Erised in the Harry Potter books, which shows "not your face but your heart's desire", aptly takes its name from the reflection of "desire".