xkill
Kill a window interactively in a graphical session. tldr-pages
On several platforms 1 Sigma rule name it
Several platforms
Display a cursor to kill a window when pressing the left mouse button (press any other mouse button to cancel)
xkillIdentifyTrips 1 Sigma rule: mediumTerminate Linux Process Via Kill by Tuan Le (NCSGroup)
Display a cursor to select a window to kill by pressing any mouse button
xkill -button anyIdentifyTrips 1 Sigma rule: mediumTerminate Linux Process Via Kill by Tuan Le (NCSGroup)
Kill a window with a specific ID (use xwininfo to get info about windows)
xkill -id window_idIdentifyTrips 1 Sigma rule: mediumTerminate Linux Process Via Kill by Tuan Le (NCSGroup)