Here are some origins of pirate words: A starboard is a steering paddle or rudder and in England, it was on the right side of the ship, hence starboard side.
The port side of a ship was originally called the larboard side, or loading side, but became verbally confusing, especially in bad weather or battles, so it was changed to port side.
Duffel is a sailor's personal belongings and the bag that carries them. It is named after the Flemish town of Duffel that produced the woolen cloth which the bags were made of.
Avast comes from the Dutch phrase 'houd vast' which meant 'hold fast' or 'stop'. Over time it became 'hou vast' and later 'avast'.
Poop deck originates from the French word for stern, la poupe. The poop deck is technically a stern deck, which in sailing ships was usually elevated as the roof of the stern cabin, also known as the 'poop cabin'. In sailing ships, an elevated position was ideal for both navigation and observation of the crew and sails.