To uninstall xfce4 just follow these instructions.
sudo apt-get remove xfce4
This will remove just the xfce4 package itself.
sudo apt-get remove --auto-remove xfce4
This will remove the xfce4 package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for xfce4 then this will work.
sudo apt-get purge xfce4
Or similarly, like this xfce4
sudo apt-get purge --auto-remove xfce4
|Maintainer||Debian Xfce Maintainers <firstname.lastname@example.org>|
|Description||Meta-package for the Xfce Lightweight Desktop Environment It aims to be fast and lightweight, while still being visually appealing and easy to use. Designed for productivity, it loads and executes applications fast, while conserving system resources.|