seaman vs Jack-tar

seaman and Jack-tar both are nouns.

Word	Noun	Adjective	Verb	Adverb
seaman	Yes	No	No	No
Jack-tar	Yes	No	No	No

As nouns, seaman and Jack-tar are synonyms defined as:

Other synonyms of seaman include gob, Jack, mariner, old salt, sea dog, seafarer, tar.

seaman (noun)	Jack-tar (noun)
a man who serves as a sailor	a man who serves as a sailor