(transitive) To eject or throw (someone or something) from or through a window.
I defenestrated a clock to see if time flies!
(transitive) To throw out; to remove or dismiss (someone) from a position of power or authority.
(computing, transitive, humorous, slang) To remove a Windows operating system from (a computer).
This posting was written on a Windows 95 PC,
Defenestrate it immediately. Install Linux. :-)
◦ Enable one-click uninstalls of unwanted OS and application features with a Defenestrate icon.
2007 May 16, Richard Stallman, speech, Free Software and Beyond: Human Rights in the Use of Software and Other Published Works,
Now of course people who want freedom shouldn't use Windows at all, you've got to defenestrate your computer, which means either you throw Windows out of the computer, or you throw the computer out the window.