Is ness a suffix or prefix?

"Ness" is not a prefix or a suffix. It is a suffix that is added to the end of a word to form a noun.

Here are some examples:

* Happy + ness = Happiness

* Dark + ness = Darkness

* Sad + ness = Sadness

* Good + ness = Goodness

The suffix "ness" typically means "state of being" or "quality of".