A careless, scatterbrained, and forgetful person; someone who is heedless and inattentive.
他总是忘带钥匙和钱包，真是个马大哈。
He always forgets his keys and wallet; he's such a scatterbrain.
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A careless, scatterbrained, and forgetful person; someone who is heedless and inattentive.