Gosh, how lovey-dovey! (3)

I believe the answer is:

coo

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'gosh' is the definition.

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

(Other definitions for coo that I've seen before include "Dove's call" , "Murmur of a dove" , "(Of pigeon) murmur" , "Call like a dove" , "Murmur, speak softly" .)

I've seen this clue in the Evening Standard.

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