privateersman vs crew member

privateersman and crew member both are nouns.

Word	Noun	Adjective	Verb	Adverb
privateersman	Yes	No	No	No
crew member	Yes	No	No	No

As nouns, crew member is a hypernym of privateersman; that is, crew member is a word with a broader meaning than privateersman:

Other hypernyms of privateersman include crewman, officer, ship's officer.

privateersman (noun)	crew member (noun)
an officer or crew member of a privateer	a member of a flight crew