You don't have to know the slang to learn how to surf, but it definitely helps. Otherwise, you won't have any idea what everyone on the beach is saying. Many surfer slang terms are self-explanatory or can be understood through context. But, if you want to prepare yourself ahead of time, consider taking the time to learn these common words and phrases.
In surfer terms, getting "axed" doesn't mean being hit with an actual ax, but it sure can feel like it. If you get axed, it means you were hit by a wave. It happens to every surfer at some point, which is likely the reason such a descriptive word exists for it.
If you're new to the surfing community, you'll likely hear this being tossed around. The word "grommet," sometimes shortened to "grom," generally refers to a new surfer. It isn't a derogatory term, but simply a statement of fact. If you don't want to be called a grommet, you'll have to earn that right on the waves.
According to the Riptionary, to "poke" is to accidentally dip the nose of your board in the water while you're dropping in on a wave. Since the goal is to keep your board above the water instead of under it, this mistake can easily lead to becoming submerged in a rushing wave. It will probably happen to you at some point, but now you have something to call it.
Being called a snake isn't a good thing; it means you're hogging all of the waves. A snake drops in when it isn't their turn, especially on a crowded day on the beach. To avoid this, make sure you pay attention to when other surfers are out there, and make room if it isn't your turn.
Offshore and Onshore
Technically, these are two surfing words, but they are equally important. If the wind is blowing offshore, it means the waves are great for surfing. If it's blowing onshore, those waves are weak. This is because an offshore wind shapes the incoming waves, making them perfect to surf. If the wind is blowing in the same direction as the waves, they have no shape or definition.
New slang words are cropping up in the surf community all the time, so don't expect to learn them all right away. The first thing you should learn is how to be a surfer, not how to speak like one. If you show up as a grommet and try to talk the talk without riding a wave or two first, you'll likely be laughed at. Instead, just get out there, learn how to enjoy the waves, and let the slang come naturally.