In Jewish mythology, a dybbuk (Yiddish: דיבוק, from the Hebrew verb דָּבַק dāḇaq meaning "adhere" or "cling") is a malicious possessing spirit believed to be the dislocated soul of a dead person. It supposedly leaves the host body once it has accomplished its goal, sometimes after being helped.
"Dybbuk" is an abbreviation of דיבוק מרוח רעה dibbūq mē-rūaḥ rā'ā ("a cleavage of an evil spirit"), or דיבוק מן החיצונים dibbūq min ha-ḥiṣonim ("dibbuk from the outside"), which is found in man. "Dybbuk" comes from the Hebrew word דִּיבּוּק dibbūq which means "the act of sticking" and is a nominal form derived from the verb דָּבַק dāḇaq "to adhere" or "cling".
The term first appears in a number of 16th century writings, though it was ignored by mainstream scholarship until S. Ansky's play The Dybbuk popularised the concept in literary circles. Earlier accounts of possession (such as that given by Josephus) were of demonic possession rather than that by ghosts. These accounts advocated orthodoxy among the populace as a preventative measure. For example, it was suggested that a sloppily made mezuzah or entertaining doubt about Moses' crossing of the Red sea opened one's household to dybbuk possession. Very precise details of names and locations have been included in accounts of dybbuk possession. Rabbi Yoel Teitelbaum, the Satmar rebbe (1887–1979) is reported to have supposedly advised an individual said to be possessed to consult a psychiatrist.
Ansky's play is a significant work of Yiddish theatre, and has been adapted a number of times by writers, composers and other creators including Jerome Robbins/Leonard Bernstein and Tony Kushner. In the play, a young bride is possessed by the ghost of the man she was meant to marry had her father not broken a marriage agreement.