In a bungling manner; clumsily or incompetently, doing something badly or making mistakes.
From 'bungle' (possibly from Scandinavian 'bung' or similar, meaning to do badly) plus '-ing' plus '-ly' to form an adverb describing the manner of action.
The word 'bungle' itself is mysterious—it might come from Northern Europe, but it perfectly captures that feeling of enthusiastically trying and completely messing things up!
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