What I just did there is, in my opinion, the only way a writer should use an uncommon word. I used the word "defenestration" (with which I assume many readers will have no familiarity), and then I immediately defined it in context.
Doing anything else is just rude.
When she was small, my daughter referred to uncommon words as "dictionary words," because they caused her to set aside whatever work she was reading and seek a dictionary.
This, of course, is not desirable for any number of reasons. It vexes the reader. It interrupts the flow of the work. And it obliterates suspension of disbelief because, in setting aside the book to seek out another, the reader is reminded that he or she was reading in the first place.
No less an authority than the late Elmore Leonard detested dictionary words. While there is no rule against them in his famous "ten rules for good writing, he does note in his rule on speaker attributions that, "I once noticed Mary McCarthy ending a line of dialogue with 'she asseverated,' and had to stop reading to get the dictionary."