I come across odd words from time to time but the two that have really stayed with me a while are
discombobulate (found this one in a Harlequin romance more than 20 years ago; I do use it from time to time, mostly when I'm being facetious

) and
cachinnation (this one I found in Jane Eyre: "
curious cachinnation" - so delightful!

)
Finding odd words is one of my favorite things about reading