Today I learned a new word here, and it is awesome:
“Platypusary” is my new favourite word, and I shall henceforth be making an effort to work it into everyday conversations whenever possible.
Thank you, Colibri, for bringing this lexical wonder to my attention.
I am curious to know what other cool or obscure words any of us have learned from reading The Straight Dope or the SDMB. Include a link to the article/thread if you can find it.
Shiboleth. At first I thought it was just a cool user-name until someone used it in a sentence–then I had to go look it up. “Shiboleth” could be a shiboleth for s’dopers.
Theist.
I have only seen that word used once outside of the SDMB.
Felch.
And I’m tempted to say “athiest”,* though I’ve spent too long hanging around talk.origins not to be familiar with that one. 
That was my answer too.
Defenestrate.
I love that word
“Cromulent”.
Widdershins
It’s a perfectly embiggened word.
Just today in GQ, knackered.
Meh.
(Please, let’s not debate it’s status as a “word” – not in this forum!)
Asshat.
It’s just “feh” with a nose job.
the other meaning of Santorum
Knackered
Which other meaning? My first encounter with the word was in its sexual sense. I didn’t learn that it was also the name of a US politician until later.
And what a disappointment that must have been.
My word: Kitteh.
I already knew the word “ensue,” but it’s taken on a whole new meaning here.
Snerk – although it’s been a while since I saw it around here.
Ossicones: the knobs on a giraffe’s head.
Derived, in the phylogenetic sense.
Cromulent: Never was a Simpsons watcher.