Any pretentious French or Latin words/phrases that academics just expect everyone to know. I think de jure/facto and vis-à-vis are fine, but they often use really far-out and strange terms too. I honestly think that academics who write papers and journals etc. just try to come across as smartass as possible at the expense of the average person's comprehension. I think its a huge problem because it keeps academia inaccessible and confined to the intellectual elite.