With Application Wizard you can easily force applications to quit.
Force an application to quit
Display the Quit menu, hold the Option key, and choose the application.
Force all applications except the active application to quit
Display the Quit menu, hold the Option key, and choose Force Quit Others.
Force all applications to quit
Display the Quit menu, hold the Option key, and choose Force Quit All.
Force all applications in a group to quit
Display the Quit menu, hold the Option key, and choose Force Quit All from the group's submenu.
Force an excluded application to quit
Display the Quit menu, hold the Option key, and choose the application from the Excluded Applications submenu.
Force all excluded applications to quit
Display the Quit menu, hold the Option key, and choose Force Quit Excluded.
Force a background-only application to quit
Display the Quit menu, hold the Option key, and choose the application from the Background-only Applications submenu.
Warning: By forcing an application to quit, you lose any changes to documents open in the application.
Related topics
Using the Quit menu
Customizing the Quit menu
Keeping applications always running