How to uninstall compiz-gtk from Ubuntu
To uninstall just compiz-gtk package itself from Ubuntu execute on terminal:
sudo apt-get remove compiz-gtk
Uninstall compiz-gtk and it's dependent packages
To uninstall the compiz-gtk package and any other dependant package which are no longer needed on Ubuntu.
sudo apt-get autoremove compiz-gtk
If you also want to delete configuration and/or data files of compiz-gtk from Ubuntu then this will work:
sudo apt-get purge compiz-gtk
To delete configuration and/or data files of compiz-gtk and it's dependencies from Ubuntu then execute:
sudo apt-get autoremove --purge compiz-gtk
compiz-gtk package information
OpenGL window and compositing manager - Gtk window decorator
Compiz brings to life a variety of visual effects that make the Linux desktop easier to use, more powerful and intuitive, and more accessible for users with special needs. This package contains a window decorator that uses Gtk to provide a look and feel similar to that of the metacity window manager.
More information about apt-get remove
Advanced Package Tool, or APT, is a free software user interface that works with core libraries to handle the installation and removal of software on Debian, Ubuntu and other Linux distributions. APT simplifies the process of managing software on Unix-like computer systems by automating the retrieval, configuration and installation of software packages, either from precompiled files or by compiling source code.
apt-get is the command-line tool for handling packages, and may be considered the user's "back-end" to other tools using the APT library.
apt-get remove is identical to install except that packages are removed instead of installed. Note that removing a package leaves its configuration files on the system. If a plus sign is appended to the package name (with no intervening space), the identified package will be installed instead of removed.