You will need to install a user script manager extension to install this script.
Visit your Ignored Users page and the script will synchronise itself with your global ignored users settings.
The following will now be hidden in topics:
Topics created by ignored users will also be hidden.
When browsing a topic, hover over a user's name to view their profile card - click the new "Ignore In This Topic" button this extension adds to ignore them in the current topic only.
The script also adds a new section to the Ignored Users page to manage users ignored in specific topics.
Please remind your fellow forumites to quote or @-mention ignore-worthy users when engaging with them.