(historical) A privately owned warship that had official sanction to attack enemy ships and take possession of their cargo. [from 17th c.]
(historical) An officer or any other member of the crew of such a ship. [from 17th c.]
An advocate or beneficiary of privatization of a government service or activity.
(motor racing, chiefly Canada, US) A private individual entrant into a race or competition who does not have the backing of a large, professional team. [from 20th c.]