/ ˌmʌmbəʊ ˈdʒʌmbəʊ; NAmE ˌmʌmboʊ ˈdʒʌmboʊ/ noun
[ U ] ( informal , disapproving ) language or a ceremony that seems complicated and important but is actually without real sense or meaning; nonsense
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WORD ORIGIN
mid 18th cent. (as Mumbo Jumbo , denoting a supposed African idol): of unknown origin; the current sense dates from the late 19th cent.