Barking sailor? (3,3)

I believe the answer is:

sea dog

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'sailor?' is the definition.
(sea dog is a kind of sailor)

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

(Other definitions for sea dog that I've seen before include "Experienced sailor (colloq.)" , "Old or experienced sailor" , "An old sailor of canine origin" , "Experienced mariner" , "mythical creature" .)

I've seen this clue in the Evening Standard.

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