What does the term salty dog mean?

Answer 1

A sailor or someone who works on or near the ocean, such as a professional whaler or fisherman. It can also mean a gin/grapefruit juice cocktail with a salted rim.

Answer 2

A "salty dog" can refer to an experienced sailor or seaman, typically someone who has spent a lot of time at sea. It can also refer to a cocktail made with vodka or gin and grapefruit juice served with a salted rim.