Something ghostly looks or sounds like a ghost — strange and chilling. A ghostly figure appearing out of the fog can seem slightly unearthly.
Distant, ghostly music sometimes echoes through an empty subway station, and ghostly voices can often be heard in stairwells or hallways, seeming to come from nowhere. Even your neighbor's glowing TV screen can appear ghostly on a dark night. The Old English root of ghostly is gastlic, which means "spiritual, holy, or not of the flesh," and also "supernatural."