Lewis Short
ob-surdesco, dŭi, 3
* V. inch. n., to become deaf (class.).
* Lit.: hoc sonitu oppletae aures hominum obsurduerunt,Cic. Rep. 6, 18, 19: si sapiens excaecatur, obsurdescat, etc., Aug. Civ. Dei, 19, 4, 4.
* Trop., to be deaf, not to give ear: obsurdescimus nescio quo modo, nec ea, quae ab eā (naturā) monemur, audimus,Cic. Lael. 24, 88: obsurduerunt aures hominum ad tam salutaria praecepta, Ambros. de Tobia, 3, 9.
Charlton T. Lewis, Charles Short, A Latin Dictionary