Clumsy, awkward, and not skillful; moving or acting in a confused and mistake-filled way.
From Middle English 'bomble' (to buzz or boom), likely imitative. It merged with Dutch or Flemish 'bombelen' (to bustle about), developing the sense of clumsy, noisy confusion.
The original sense of 'bumble' was the buzzing sound a bee makes—so 'bumbling' is literally like being as chaotic and noisy as a bee blundering around a room. It's onomatopoeia that became a personality trait.
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