Meaning

originUnknown, from pidgin, possibly from an Australian Aboriginal language, although it appears also to have moved from pidgin to Aboriginal. Numerous derivations have been proposed. * Mr A. Meston of Brisbane, in the Sydney Bulletin of 18 April 1896, cited Aboriginal words jimba, jombock (also jombok), dombock and dumbog, all meaning "white mist preceding a shower," which a flock of sheep supposedly…

Etymology from Wiktionary, CC BY-SA 3.0