there is an image out there of a surfer who has dreadlocks, smokes weed all the time, has no job, dirty clothes and talks in a language undecipherable to the rest of the world. This isn't true really but words that are around but never really used can be...
Drop in - to catch a wave as it peaks and ride down the face
Drop in on - catch a wave that someone else is already riding. They are normally closer to the shoulder than you.
Barrelled - get inside a hollow wave so you are "in the tube" of the wave (the typical photo of a surfer.
ripping - this is used a few ways, if you were ripping you were using the waves perfectly, turning hard on the top doing everything perfect. if the conditions are ripping, they allow you to do that.
slashing - turning hard on the top of the wave, spraying water from the fins. like someone slashed through the wave with a knife.
gnarly - insanely awesome
hang ten - rind the nose of the board with all ten toes hanging off the end
blown out - waves destroyed by the wind
close out - whole wave breaks at once so there is no ridable face
shore break - waves right next to the shore line
shore dump - big waves right next to the shore line that tend to be closing out.
set - waves come in groups called sets. these are, usually, 3 waves that are larger than the others. this is caused by waves moving at different speeds out a sea due to their size
over the falls - getting pulled round by a breaking wave, right where it starts to break. so you are pulled up the face of the wave then pushed forward by the breaking lip. kind of looks like you are going over a water fall
on the head - be beaten by breaking waves, or broken waves. usually when in trouble or trying to get out. "parko just took a massive set on the head"
hold down - pushed under water by a wave, sometimes pressed against the sea floor or the reef, to the point you can't get back up. this can be so bad that you get to the surface with only enough time to get one breath before the next wave does the same. that s a 2 wave hold down
left hander - this is a wave that breaks from left to right as you look at it from shore
right hander - the opposite
backside - turning at the top of the wave when you are looking down the face instead of the face.
frontside - turning at the top of the wave where you are facing the wave's face (these are easier)
Regular and Goofy - Regular means that you surf with your right foot at the back of the board, goofy is with the left. this means if you are regular you ride left handers mainly doing backside turns and visa versa.
that is all i can think of right now really, hope this helps