I'm surprised there are no tips on exclusive (3)

I believe the answer is:

coo

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'i'm surprised' is the definition.
(exclamation of surprise)

I don't understand the rest of the clue.

(Other definitions for coo that I've seen before include "Soft murmuring sound of a pigeon" , "Surprised expression" , "Breathe" , "Speak fondly" , "Gosh!" .)

I've seen this clue in The Times.

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