There are many ways to clip in Ocarina of Time. Clipping allows one to escape the normal playing bounds of the game, which can lead to some major breaks.
For nearly any angle less than 90 degrees, a jumpslash will be able to push you through one side of the wall. For angles a jumpslash can't get through, a superslide usually can. Other ways to clip through acute angles include recoil boosting and Hyper Extended Supersliding. Superslides can get through some 90 degree angles, but only if one of the two walls is an actor.
There are some specific objects that you can use to clip. Specifically, the blocks you can push, even though they create a 90 degree angle, can be clipped through. These objects, when up against a wall, can be clipped through a variety of ways. These objects can be clipped through with Recoil boosts, Jumpslashes, Superslides/HESS's, Damage Boosts, and Giant's Knife/Biggorons Sword Thrusts, depending on the object. This is particularly useful in the Fire Temple. Additionally, you can use an armos that you push around to clip as well. This is useful for a Trials Skip. There are also objects, like the hammer blocks in the fire temple you can clip through as well. Wooden boxes and Hammer blocks against a wall can be clipped through as an adult with a precisely angled jumpslash, but only if there is solid ground behind the wall.
With the third thrust of either the Giant's Knife (can be broken too) or the Biggoron Sword, it is possible to clip through these objects in the game. Typically the hover boots are used as well, so that once you clip out of bounds you have time to get back inside where you are trying to go. The Door of Time is one of these objects near a wall that has a small space in between that allows clipping.
Get near a wall and a hookshot-able object (a torch, freezard, iron knuckle, likelike, etc.) close to the wall. Pull out your hookshot and press Z to go to 3rd person. Move sideways towards the hookshot-able object so that you are being sqeezed between it and the wall, then use the hookshot and you should go through the wall. It is also possible to do this without z-targeting if you aim correctly.
As child link, when you grab a climbable wall from air, link will clip slightly inside the vines/gate for a few frames. If you get hit during these few frames, you will completely clip through the wall. This does not work on ladders.
While letting go of a vine, press down then up. This will cancel the lag and allow you to regrab faster. Also, you can do it to skip a rung at the top of a climbable wall, and can use it to do wallclipping with bombchus easier, and without needing to fall an unnecessary distance.
It is possible as an adult to use the hookshot and shoot across the top of a ladder. If done correctly you will grab the top of the ledge inside of the ladder. From there you can release the ledge by pressing A and then quickly pressing B to jumpslash and get out of bounds. Ladder clipping can be done without a hookshot by performing a sidehop or precisely angled backwalk. These two ways also cause link to grab the ladder differently, meaning a sword is not needed to jumpslash after letting go. Instead, simply hold the direction you want to fall after letting go of the ladder to not clip back inbounds. Ladder clipping only works as Adult because Child Link will pop back up after dropping from the ladder.
Grunz clipping is a nickname for clipping through an angle of 90 degrees or less formed by two walls that have ledges on top of them which can be grabbed. By grabbing the correct part of the ledge, the majority of Link's body will be inside the wall. Getting damaged while mostly clipped will push you through the wall.