SEAL vs sailor boy

SEAL and sailor boy both are nouns.

Word	Noun	Adjective	Verb	Adverb
SEAL	Yes	No	No	No
sailor boy	Yes	No	No	No

As nouns, sailor boy is a hypernym of SEAL; that is, sailor boy is a word with a broader meaning than SEAL:

SEAL: a member of a Naval Special Warfare unit who is trained for unconventional warfare
sailor boy: a serviceman in the navy

Other hypernyms of SEAL include bluejacket, navy man, sailor.

SEAL (noun)	sailor boy (noun)
a member of a Naval Special Warfare unit who is trained for unconventional warfare	a serviceman in the navy