as much food as your belly can hold; also means as much of something as you can tolerate or handle.
From 'belly' (from Old English 'belg', bag) + 'full' (from Old English 'full'). This compound is straightforward: belly + ful of something.
A bellyful has two meanings that reveal human nature perfectly—we use the same word for being completely satisfied with food and completely fed up with nonsense.
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