a robber on the high seas; one who by open violence takes the property of another on the high seas; especially, one who makes it his business to cruise for robbery or plunder; a freebooter on the seas; also, one who steals in a harbor.-an armed ship or vessel which sails without a legal commission, for the purpose of plundering other vessels on the high seas.-one who infringes the law of copyright, or publishes the work of an author without permission.-to play the pirate; to practice robbery on the high seas.-to publish, as books or writings, without the permission of the author.