I can't speak for Office 2011, but my Office 2008 installation may be of some help. Located in /Applications/Microsoft Office 2008/Additional Tools/Remove Office, there is a Remove Office.app. Check out your installation to see if you have something similar.

Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365