Gnash

1. (v. t.) To strike or grind together in anger; as, to gnash the teeth.

2. (v. i.) To grind or strike the teeth together.

Thesaurus Entries

bite, bolus, champ, chaw, chew, chew the cud, chew up, chomp, cud, gnaw, gob, grind, gum, masticate, morsel, mouth, mouthful, mumble, munch, nibble, nip, quid, ruminate, snap, swallow