ETYM From Private.
1. A privately owned warship commissioned to prey on the commercial shipping or warships of an enemy nation.
2. An officer or crew member of a privateer; SYN. privateersman.
Privately owned ship commissioned by government to attack enemy vessels; captain or seaman of privateer.
Privately owned and armed ship commissioned by a state to attack enemy vessels. The crews of such ships were, in effect, legalized pirates; they were not paid but received a share of the spoils. Privateering existed from ancient times until the 19th century, when it was declared illegal by the Declaration of Paris 1856.
privateersman