Definition from Wiktionary, the free dictionary
seadog (plural seadogs)
- A sailor accustomed to the sea.
- The old seadog knew the storm was coming long before the rest of the crew were aware of it.
- (archaic) A seal (marine mammal), or a similar design in heraldry.
- (uncommon) An omen of bad luck.
- (uncommon) A white-topped wave in an estuary.
sailor accustomed to the sea
dogfish — see dogfish