HAUNTED

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."

Of a location, frequented by a ghost or ghosts.

"The hotel was haunted by a disembodied spirit."

Obsessed (by an idea, threat, etc.).

"a soldier haunted by the memories of combat"

Showing a feeling of being disturbed.

"a haunted expression"