Ahoy! ~ "Hello!"
Avast! ~ "Hey!" "Stop!" "No way!"
Aye ~ "Yes, I most heartily agree."
Aye aye! ~ "Absolutely, I'll see to it as soon as I finish my nap."
Arrr ~ Can mean "yes," "I'm happy." or "Great beer!" Not to be confused with "Aarg!" (which is the sound you make when you accidentally sit on the sharp pointy end of an anchor!)
Beauty ~ Pirate word for a wench, always preceded by 'me,' as in "Why are ye walkin' away, me beauty?"
Bilge rat ~ A first rate insult, as in "Belay that racket, ye smarmy bilge rat." The bilge is the lowest deck of the ship, usually filled with slimy water. Of course, if someone made me stay in the bilge, I'd make a racket too!
Grog ~ Watered rum. Since water onboard was stored in slimy wooden barrels, it was usually anything but fresh. Grog helped kill the rancid taste. And several thousand brain cells.
Hornpipe ~ A single reed flute and the wild dance usually done to its music. Not to be confused with the pirate pick up line, "No, me beauty, that's not a hornpipe in me pocket. I really am happy to see ye!"
Keelhaul ~ A really horrible way to spend an afternoon. Pirates who violated one of the articles (rules they all voted on and agreed to before the voyage began) might be punished by being tied to a rope that ran under the keel of the ship. The offender was shoved into the water on one side of the ship, dragged against the barnacled-covered hull and hauled out on the other. Rinse, and repeat.
Lubber ~ An insulting word for a landsman. No one wants to be a lubber.
Smartly ~ To do something quickly. As in "Nip over to the bookstore smartly and claim your copy of PLEASURING THE PIRATE before they're all gone!"