Doctor? Yes and No! Perhaps a pretentious “Medical Officer” (5)

I believe the answer is:

quack

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'doctor?' is the definition.
(quack is a kind of doctor)

I don't understand how the remainder of the clue works.

(Other definitions for quack that I've seen before include "Bogus doctor" , "Mountebank medic" , "Duck's cry or dud doctor" , "Noise of a duck" , "Pseudo doctor" .)

I've seen this clue in The Hindu.

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