privateer vs privateersman

privateer and privateersman both are nouns.

Word	Noun	Adjective	Verb	Adverb
privateer	Yes	No	No	No
privateersman	Yes	No	No	No

As nouns, privateer and privateersman are synonyms defined as:

privateer (noun)	privateersman (noun)
a privately owned warship commissioned to prey on the commercial shipping or warships of an enemy nation	an officer or crew member of a privateer
an officer or crew member of a privateer