HAUNTING

To inhabit, or visit frequently (most often used in reference to ghosts).

"A couple of ghosts haunt the old, burnt-down house."

To make uneasy, restless.

"The memory of his past failures haunted him."

To stalk, to follow

"The policeman haunted him, following him everywhere."

A particular instance of haunting; a ghostly habitation.

"During the haunting, strange voices and noises were heard and objects flew off tables."

Remaining in the mind; not easily forgotten.

"He had a haunting gaze."