(verb) : in-frendĕo, ēre, and in-frendo, ĕre
* To gnash the teeth (poet. and postclass.): dentibus infrendens gemitu,Verg. A. 3, 664: ac simul infrendens,Stat. Th. 5, 663: infrendite, inspumate,Tert. Apol. 12.
* To gnash the teeth at, threaten furiously; with dat.: aliis infrendentem,Stat. Th. 8, 580.