To uninstall focuswriter just follow these instructions.
sudo apt-get remove focuswriter
This will remove just the focuswriter package itself.
sudo apt-get remove --auto-remove focuswriter
This will remove the focuswriter package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for focuswriter then this will work.
sudo apt-get purge focuswriter
Or similarly, like this focuswriter
sudo apt-get purge --auto-remove focuswriter
|Maintainer||Barak A. Pearlmutter <email@example.com>|
|Description||Fullscreen distraction-free writing program|