Ghostly noise can refer to two different sounds: a MOAN and a GROAN. A MOAN is a low, mournful sound usually made in pain or sorrow. It is often associated with ghosts and other supernatural entities. A GROAN is a deep, guttural sound that is usually made in response to physical or emotional pain. It is also often associated with ghosts and other supernatural entities. Both of these sounds are commonly used to create a spooky atmosphere in horror films and other media.