xkill

Kill a window interactively in a graphical session. See also: kill, killall. More information: https://www.x.org/releases/current/doc/man/man1/xkill.1.xhtml.

• Display a cursor to kill a window when pressing the left mouse button (press any other mouse button to cancel):

xkill

• Display a cursor to select a window to kill by pressing any mouse button:

xkill -button any

• Kill a window with a specific ID (use xwininfo to get info about windows):

xkill -id id