German word meaning “noisy spirit”.  Polturn to knock + Geist spirit

Merriam-Webster defines it as:  a noisy usually mischievous ghost held to be responsible for unexplained noises (as rappings)

Most poltergeist experiences are reported to begin with unexplained noises from within the dwelling.  Typically for a poltergeist to occur there is a need for a proxy.  A strong theory is that adolescent females may be the most likely to become an advocate to a poltergeist.  The theory is based on studies that show females ages 13 through their early twenties tend to go through serious psychological and physical changes.  This could allow the poltergeist to take advantage of its vulnerable prey.  However, don’t be fooled.  Anyone at anytime could become an agent to a poltergeist. Psychokinesis is thought to be the mental component that allows the agent to unconsciously cause the audible and physical disturbances.   

Poltergeist experiences have been known to possess some or all of the following claims:  

• banging on walls
• rapping on windows
• unexplained sounds that come from literally nowhere
• objects being thrown through the air
• objects dropping at your feet crashing to the ground causing them to break
• things disappearing and reappearing
• beds shaking

On some rare occasions claims have been as follows:

• Small fires
• Water seemingly dripping from nowhere
• Apparitions being seen

Psychokinesis

Merriam-Webster definition:  movement of physical objects by the mind without use of physical means