I did this on Firefox, but I suspect it may work in other browers too.

1. Install the Violentmonkey extension. Tampermonkey or Greasemonkey will also do.
2. Install the Lemmy tools script.
3. Browse to Lemmy
4. Click on the screw driver icon on the LemmyTools bar that is now visible on the Lemmy page.
5. Scroll down and check the box next to “Content Blocking”
6. Add your block words in the “Add filters seperated by commas.” box. I typed “Trump, Vance” Voila!