Past tense of bung; to plug, stop up, or block an opening, often hastily or temporarily; to throw or toss something.
From 'bung' (a stopper or plug), with regular English past-tense -ed suffix; 'bung' itself has unknown origin, possibly from Dutch 'bonghe' or related to the sound of impact.
The word 'bung' has a wonderfully onomatopoetic quality—it sounds like the action it describes, which is why it's survived in British English as casual slang.
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