coastguardsman vs sailor

coastguardsman and sailor both are nouns.

Word	Noun	Adjective	Verb	Adverb
coastguardsman	Yes	No	No	No
sailor	Yes	No	No	No

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

Other hypernyms of coastguardsman include bluejacket, navy man, sailor boy.

coastguardsman (noun)	sailor (noun)
a member of a coastguard	a stiff hat made of straw with a flat crown
	any member of a ship's crew
	a serviceman in the navy