I carry this blue notebook around, filling it up with words and definitions that I've never heard before or want to use in a story or article. Once the book is bursting with knowledge, I buy a new one. All definitions come from Merriam Webster except convivial that I found at Dictionary.
Arbitrage - the nearly simultaneous purchase and sale of securities or foreign exchange in different markets in order to profit from price discrepancies. First known use: 1875.
Rive - to wrench open or tear apart or to pieces. First known use: 14th century. Just used this palabra in my latest article at LitReactor.
En prise - of a chess piece; exposed to capture. First known use 1825.
Triumphalism - an attitude or feeling of victory or superiority. First known use 1964.
Convivial - friendly; agreeable. First known use 1660-1670.
Abrogate - to abolish by authoritative action. First known use circa 1520.
Specious - having deceptive attraction or allure; having a false look of truth or genuineness. First known use: 1513.