To do very little or accomplish nothing of importance; a person who accomplishes nothing.
From 'do' (Old English 'don') combined with 'little.' Created as a descriptive phrase that became a surname, most famously for Doctor Dolittle, the fictional character who talks to animals.
Hugh Lofting's Doctor Dolittle series started in 1920 and became famous partly because the name is so clever—a doctor with an unusual specialty who literally 'does little' in conventional medicine.
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