$ sudo apt-get remove ibus-gtk 

Uninstall ibus-gtk including dependent package

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

$ sudo apt-get remove --auto-remove ibus-gtk 

Use Purging ibus-gtk

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

$ sudo apt-get purge ibus-gtk 

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 ibus-gtk 

See Also,