What is the suffix FOR citizen?

There isn't a specific suffix for "citizen" in the way you might be thinking. "Citizen" is a complete word on its own.

However, we can talk about:

* Citizenship: This is the noun form referring to the state of being a citizen.

* Citizens: This is the plural form of the word "citizen".

Let me know if you'd like to explore other aspects of the word "citizen" or related concepts!