If you've added a font to your website that you would like to remove, you can do so by opening your Font Manager by:
Pressing Shift F
Clicking on Window > Font Manager
In either Global Styles or the Font Panel click on the Add Font button
Once you're in the Font Manager, in the upper right where it says Website Fonts you can click into that to select Default Fonts, then depending on the type of font you want to delete you'll select between Google Font, Adobe Font, Uploaded Font, or Default Font, and click on the Delete button under whichever font name you want to remove.
Keep in mind that when you delete a font it will remove it from any site it was used on.