privateer

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A ship privately owned and crewed but authorized by a government during wartime to attack and capture enemy vessels.
2. n. The commander or one of the crew of such a ship.
3. v. To sail as a privateer.

Century Dictionary and Cyclopedia

1. n. An armed vessel owned and officered by private persons, but acting under a commission from the state usually called letters of marque. It answers to a company on land raised and commanded by private persons, but acting under regulations emanating from the supreme authority, rather than to one raised and acting without license, which would resemble a privateer without commission. (Woolsey, Introd. to Inter. Law, § 121.)
2. n. The commander of, or a man serving on board of, a privateer.
3. To cruise in a privateer for the purpose of seizing an enemy's ships or annoying his commerce. Privateering was abolished by the treaty of Paris of 1856, and this article has been assented to by nearly all civilized nations; the most prominent exception is the United States.

Wiktionary

1. n. nautical A privately owned warship that had official sanction to attack enemy ships and take possession of their cargo.
2. n. An officer or any other member of the crew of such a ship.
3. n. motor racing A private individual entrant into a race or competition who does not have the backing of a large, professional team.
4. v. To function under official sanction permitting attacks on enemy shipping and seizing ship and cargo; to engage in government-sponsored piracy.

GNU Webster's 1913

1. n. An armed private vessel which bears the commission of the sovereign power to cruise against the enemy. See Letters of marque, under marque.
2. n. The commander of a privateer.
3. v. To cruise in a privateer.

WordNet 3.0

1. n. a privately owned warship commissioned to prey on the commercial shipping or warships of an enemy nation
2. n. an officer or crew member of a privateer