Has normal / light signs of use such as rub marks, shining and maybe some light scratches.
Has light to moderate amounts of fungus will have very little impact if any on the image quality.
Most used lenses will have some amounts of internal dust as they are not hermetically sealed units! The action of focusing and zooming over time draws dust in some more than others. While it might be a unwelcome addition to a lens the impact to image quality is minimal if any.
Average amount of internal dust for a used lens.
Works with all olympus OM system cameras