Gone Davy Jones Locker is a slang term that means someone or something has been lost at sea. There are various synonyms for this phrase that are commonly used, such as "lost at sea", "sunk", "underwater", "submerged", "vanished", "disappeared", "swallowed up", "gone down", and "deep-sea grave". These words are used to describe situations when something or someone is no longer visible or traceable in the ocean. The usage of these words depends on the context and the severity of the loss. While they may imply a tragic incident, they can also be used in a lighthearted way, such as when referring to a misplaced object or a forgotten memory.