Navy SEAL vs navy man

Navy SEAL and navy man both are nouns.

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

As nouns, navy man is a hypernym of Navy SEAL; that is, navy man is a word with a broader meaning than Navy SEAL:

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

Other hypernyms of Navy SEAL include bluejacket, sailor, sailor boy.

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