flibbertigibbet \ FLIB-er-tee-jib-it \ noun
1. Archaic . a gossip.
2. a chattering or flighty, light-headed person.
Believe it or not, this word sounded familar, then I remembered hearing it in one of the Harry Potter movies - or maybe I read it in one of the books - but I didn't remember in which book or movie or in what context. Thanks to the World Wide Interwebs, I was reminded it was used as a password to get into the Gryfindor dormitory. I also discovered it was used in the song "Maria" in the 1959 musical The Sound of Music as well as in the Tom Hanks movie Joe Versus the Volcano.
I'm betting that I'll never read the word ever again in my life and I'm absolutely certain I'll never use it in conversation, even though I know a few flibbertigibbets.