What is a suffix for done?

There isn't a single, specific suffix for "done". However, depending on what you want to convey, you could use suffixes like:

* -ness: This creates an abstract noun, focusing on the state of being done. Example: "completeness"

* -ed: This indicates a past tense, focusing on the action of completing something. Example: "finished"

* -ing: This indicates an ongoing action, focusing on the process of being done. Example: "finishing"

* -able: This indicates the potential for something to be done. Example: "doable"

You can also combine "done" with other words to create new phrases, like:

* Well-done

* Overdone

* Half-done

* All done

The best option depends on the context and what you want to emphasize.