re: What fancy words annoy you?

Nonplussed. I generally like words that have very specific meanings as I likely have a German-speaking brain in an English-tethered body so nonplussed is right up my alley. However, fifty percent of the time it is used the person means the exact opposite and it is often difficult to tell if they are using it correctly. I also assume if I use it there is a decent chance someone will think I mean the opposite of what I am trying to convey.