However, we can get creative and play with the concept:
* "Madam, I'm Adam" is a famous palindrome, and while it doesn't directly mean "expression of", it could be interpreted as an expression of introduction or self-identification.
* "Racecar" or "Level" are palindromes that could represent the act of "expressing" something, like speed or a certain level of achievement.
Ultimately, the meaning of a palindrome is open to interpretation and depends on the context in which it's used.
If you're looking for a specific type of expression, it might be helpful to provide more context. For example, are you looking for a palindrome that expresses:
* Love?
* Anger?
* Joy?
* A specific concept?
With more information, we might be able to find a palindrome that better suits your needs.