[rainingcatndogs]

You can try this plugin: https://addons.mozilla.org/en-US/firefox/addon/ddg-hide-unwa...

[spurgu]

Thanks! Someone in another thread recommended this userscript, which adds a small "Block" button next to search results in many search engines:

https://greasyfork.org/en/scripts/1682-google-hit-hider-by-d...

[crtasm]

Another approach for Firefox (not sure about other browsers):

Right click on the search box on a website and 'Add a keyword for this search', save it then edit the bookmark to end up with something like https://duckduckgo.com/?t=h_&q=-site:example.com %s