Old salt (3,3)
'old salt' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for sea dog that I've seen before include "Ancient Mariner" , "Old tar" , "Experienced mariner" , "'Old salt (3,3)'" , "mythical creature" .)
(Other definitions for seadog that I've seen before include "Mate, perhaps" , "Rating" .)
'old salt' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tar that I've seen before include "Hearty" , "Sailor (colloq.)" , "Black substance in cigarettes" , "Road surfacing or old sailor" , "Product of coal" .)