For more see index.
How To Block Works & Authors (from showing up in your search)
Ao3 has a block/mute function built in to the site, but that only stops the blocked party from being able to interact with your fics. That may work fine for some people such as those spamming your works with unwanted comments, or someone being mean. But many times when you block someone it is because you just don't want to see anything to do with that person i.e any of their works, and therefore the built in block is not much help. There is a way to properly block a user or a particular work from showing up in your searches though, using site skins as always!
How To Block A User:
To block a user simply go into the 'Custom CSS' box of your site skin, and paste this piece of code:
.user-000 { display: none !important; }
This will do nothing if left as is, the '000' is a placeholder for the user ID of the person you want to block. I will use mine as a demonstration of how it works (please don't block me, I'm your friend).
My user ID is:5135567
e.x.
.user-5135567 { display: none !important; }
How To Block Works:
Sometimes there is a particular work, maybe for a fandom or ship you're into, that for whatever reason you have no interest in reading but it shows up every time you look for fics. Whatever reason you want to block a work, be it a fic that's triggering for you, one you dislike that's continually updating to the top of the tag, or just an annoying fic with waaaaaaaaay too many tags, to block a work simply go into the 'Custom CSS' box of your site skin, and paste this piece of code:
.work-000 { display: none !important; }
Again the '000' is a placeholder for the work no. which is a set of numbers unique to every work on ao3. I will use this work no. to demonstrate (this work no is no longer a part of ao3, but the example servs it's purpose).
https://archiveofourown.org/works/58275322
e.x.
.work-58275322 { display: none !important; }
Now running this code would block the work from appearing in your search.