Mordâcitas, pen. cor. mordacitâtis, f. g. Plin. Byting: shatpnesse of wordes.
Lewis and Short: Latin dictionary
mordācĭtas, ātis, f. [mordax], the power of biting or stinging, mordacity (post-Aug.): urticarum foliis inest aculeata mordacitas, Plin. 21, 15, 54, 91: vinosa,