irrefragable: Dictionary.com Word of the Day. irrefragable [Dictionary.com Word of the Day]
I don't mean to brag, but it's rare these days for me to run across a non-technical word that I've never seen before. (By non-technical, I mean words that don't derive from science or mathematics or engineering. Anyone can aim the name of a chemical compound my way.)
Irrefragable makes me very happy.