Lewis & Short

frendo and frendeo, frendui, frēsum and fressum (v. infra), 2 and 3, v. n. and a. [cf. Gr. χρεμ-ίζω, to neigh, χρόμη; Germ. greinen, grinsen, Fick, Vergl. Wörterb. p. 72].

  1. I. Neutr., to gnash the teeth (for syn. cf. fremo): ego illum male formidabam, ita frendebat dentibus, Plaut. Capt. 4, 4, 5; id. Truc. 2, 7, 41: Nemeaeus leo Frendens efflavit graviter extremum halitum, Cic. poët. Tusc. 2, 9, 22: frendens aper, Ov. A. A. 1, 46: et graviter frendens sic fatis ora resolvit, Verg. G. 4, 452: tumidā frendens Mavortius irā, Ov. M. 8, 437: (Hannibal) frendens gemensque ac vix lacrimis temperans dicitur legatorum verba audisse, Liv. 30, 20, 1: frenduerunt super me dentibus suis, Vulg. Psa. 34, 16.
    Poet. transf.: dolor frendens, Sen. Herc. Fur. 693.
    With acc.: nec, machaera, audes dentes frendere, Plaut. Fragm. ap. Non. 447, 18.
  2. II. Act.
    1. A. To crush, bruise, or grind to pieces (as if gnashing the teeth): porci dicuntur nefrendes ab eo, quod nondum fabam frendere possunt, id est frangere, Varr. R. R. 2, 4, 17: saxo fruges frendas, Att. ap. Non. 437, 21 (Rib. Fragm. Trag. v. 478); Pac. ib. (Rib. Fragm. Trag. v. 11): fresi et aqua macerati ervi sextarius, Col. 6, 3, 4: fresa cicera, id. 2, 10, 35: faba fresa, id. 2, 11, 7; 6, 3, 5; for which: faba fressa, Cels. 5, 18, 21.
    2. B. To lament over with rage, gnash the teeth at: frendēre noctes, misera, quas perpessa sum, Pac. ap. Non. 447, 17 (Rib. Fragm. Trag. v. 10).
      With object-clause: frendente Alexandro, eripi sibi victoriam e manibus, Curt. 4, 16, 3.