Long-tap a bookmark and select Remove. https://support.mozilla.org/en-US/kb/firefox-android-faq?esab=a&s=delete+bookmark&r=9&as=s#w_how-do-i-remove-a-bookmark

What an absolutely terrible interface!

- I should have the option to remove this "Top Sites" nonsense COMPLETELY, for good. - Why does it even persist between launches of the browser? The privacy settings should allow automatic deletion of history on browser exit. - Why should I have to *constantly* be reminded to synch. Remove it!

This is IDIOT DESIGN. Even the default browser is better than this.

I wholeheartedly agree. I have a string of bookmarks that go on forever. I use Xmarks and I wish the Android Firefox had an add-on like the windows Firefox does.

Long press on item brings up the following options: Open in New Tab, Open in Private Tab, Edit, Pin Site.

There is no "Remove".

Had to remove offending site from History. Once I did that, it no longer appeared in Top Sites.

It's a huge pain in the ass to search out every instance of a site in your history, but it works.