Lewis & Short

vānĭlŏquentĭa, ae, f. [vaniloquus], empty or idle talk, prating, vaunting (rarely; not in Cic.), Plaut. Rud. 4, 1, 14: hac vaniloquentiā primum Aristaenum praetorem Achaeorum excitavit, Liv. 34, 24, 1; Tac. A. 3, 49; 6, 31.
Plur., Jul. Val. Rer. Gest. Alex. 2, 10.