sailor boy vs SEAL

sailor boy and SEAL both are nouns.

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

As nouns, SEAL is a hyponym of sailor boy; that is, SEAL is a word with a more specific, narrower meaning than sailor boy:

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

Other hyponyms of sailor boy include coastguardsman, Navy SEAL, striker, submariner.

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