n. A malicious possessing spirit, believed to be the dislocated soul of a dead person.
the GNU version of the Collaborative International Dictionary of English
n. the wandering soul of a dead person, or a demon, that enters the body of a living person and controls that body's behavior. It may be exorcised by religious rites.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. (Jewish folklore) a demon that enters the body of a living person and controls that body's behavior
Word Usage
"The wife replies that her husband is mistaken, the relative has been dead for three years, and what her husband saw was a dybbuk a Yiddish word used in this context to mean “evil spirit”."