However, depending on the context, other words might be more suitable:
* Ysbryd angau: This literally means "death spirit" and can be used for a ghost specifically.
* Ysbryd ysbrydol: This translates to "spiritual spirit" and can be used for a ghost in a more general sense.
* Creadur ysbrydol: This translates to "spiritual creature" and can be used for a ghost or other supernatural being.
The best translation will depend on the specific context and the nuance you want to convey.