$ sudo apt-get remove fenics 

Uninstall fenics including dependent package

If you would like to remove fenics and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove fenics 

Use Purging fenics

If you use with purge options to fenics package all the configuration and dependent packages will be removed.

$ sudo apt-get purge fenics 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove fenics 

See Also,