τρίζω G5149
trízō · trid'-zo · Verb
apparently a primary verb; to creak (squeak), i.e. (by analogy) to grate the teeth (in frenzy):--gnash.
1 Occurrence in the King James Bible
Mark 9:18And wheresoever he taketh him, he teareth him: and he foameth, and gnasheth with his teeth, and pineth away: and I spake to thy disciples that they should cast him out; and they could not.