pedantry; showing off one's knowledge
Refers to the act of flaunting one's learning or being overly concerned with minor academic details. Often used critically.
His talk was nothing but pedantry, and the listeners looked bored.
It's more important to explain things clearly than to show off your learning.
From Chinese 衒學 (xuànxué), literally 'to show off learning'. The kanji 衒 means 'to display' or 'to show off', and 学 means 'learning'.