(v.) The act of throwing one's excrement out the window (especially when experiencing plumbing issues in another's home that may lead to greater embarrassment than the act of defenescating itself).
When the toilet failed to flush when I visited my future in-laws for the first time, I felt compelled to defenescate rather than own up to my unsightly mess.
The act of bodily thowing a person out of a window. Defenestration is best executed from a third story (glass) window as it breaks bones but allows the defenestree to limp away.
Defenestration first officially happened at the Defenestration of Prague in 1618, leading to the start of the 30 years war.