Definitions by Achim S.

poltergeist 

A kind of ghost that manifests itself by physical activity (moving things, slamming doors/windows, etc.)
The words Polter and Geist seem to be of German origin:
"Polter" = to make knocking sounds
"Geist" = German for "ghost"

the house is haunted by a poltergeist

poltergeist by Achim S. April 14, 2006