To give you a more helpful answer, could you please clarify what you mean by "poli"? For example:
* Is it a part of a name? (e.g., "Poli" in "Poliana")
* Is it a shortened form of another word? (e.g., "politician")
* Is it a word in a specific language?
Once I know what you mean, I can help you find the feminine form if it exists.