Most mobile clients allow you to hide posts that contain a certain keyword in their title. Here's a non-exhaustive list of clients that support keyword filtering off the top of my head:
- Voyager (multiplatform; I believe you need to have the app because the option doesn't show up on the website for me)
- Mlem (iOS)
- Arctic (iOS)
- Thunder (Android)
- Sync (Android)
I don't know of any that can hide posts with a keyword mentioned in any of the post's comments; doing so would require the client to make a lot of extra API requests.
https://www.youtube.com/watch?v=BMs5dcHvW4Q