The term "jack-tar" is an informal way of referring to a sailor or seafarer. There are several synonyms for this term, including "mariner," "seaman," "salt," "able seaman," and "tar." Each of these terms is commonly used to describe someone who works on a ship or has a career in the maritime industry. However, the term "jack-tar" is considered somewhat outdated these days and is rarely used in modern times. Regardless of which term is used, sailors and seafarers play a vital role in shipping, navigation, and the transportation of goods and people across the world's oceans.