*A ghost or spirit of a dead person.
People say there are ghostly apparitions [ghosts/phantoms] in this house.
The soul of a dead person thought of especially as appearing to living people.
An unusual or unexpected sight.
A ghostly figure*.
An apparition is the ghostly sighting of a spirit, entity or a deceased person often described as transluscent and wispy in appearance.
*Britannica/Merriam-Webster.