1) Literary pirate 2) Pirate 3) Plagiariser 4) Plagiarist 5) Stealer 6) Thief 1) Pirate 2) Plagiariser 3) Plagiarist 
plagiarizer Someone who uses another person's ideas or a part of her/his work and pretends that it is the creation of the one who is doing the 'borrowering'; whether intentional or not.