jack-tar

Jack Tar was the common Englishman's name for the sailors of the Royal Navy during the time of the British Empire. Tar by itself was a synonym for sailor. Jack Tar was a personification of a sailor.There are three plausible etymologies for this name. Sailors frequently wore coats and hats made from a waterproof fabric called tarpaulin. This may have been shortened to "tar" at some point.It was common amongst seamen to plait their long hair into a pigtail and smear it with high grade tar to prevent it getting caught in the ship's equipment. This practice continued until the early 20th century.In the age of wooden sailing vessels, a ship's rigging was rope made of hemp, which would rot quickly in such a damp environment. To avoid this, the ropes and cables were soaked in tar. Since it was a routine part of a sailor's day to "clap on to" and "heave" these ropes, his hands would be stained with tar, and thus earned the nickname "tar".
See more at Wikipedia.org...

Noun
1. a man who serves as a sailor
(synonym) mariner, seaman, tar, Jack, old salt, seafarer, gob, sea dog
(hypernym) sailor, crewman
(hyponym) able seaman, able-bodied seaman