navy man vs SEAL

navy man and SEAL both are nouns.

Word	Noun	Adjective	Verb	Adverb
navy man	Yes	No	No	No
SEAL	Yes	No	No	No

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

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

Other hyponyms of navy man include coastguardsman, Navy SEAL, striker, submariner.

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