pirate

noun

1.
someone who uses another person's words or ideas as if they were their own
brain-stealer thought-thief literary pirate plagiariser plagiarist plagiarizer
Derived from:
pirate piratical
2.
someone who robs at sea or plunders the land from the sea without having a commission from any sovereign nation
seareaver sea-robber shaythman wiking buccaneer sea robber sea rover
Derived from:
piratical
3.
a ship that is manned by pirates
pirate ship
Derived from:
pirate piratical