τρίζο trizo trid'-zo Apparently a primary verb; to creak (squeak), that is, (by analogy) to grate the teeth (in frenzy)KJV Usage: gnash.
Mark 9:18 (KJV_Strongs) 18 G2532 And G3699 wheresoever G302 G2638 he taketh [G5632] G846 him G4486 , he teareth [G5719] G846 him G2532 : and G875 he foameth [G5719] G2532 , and G5149 gnasheth [G5719] G846 with his G3599 teeth G2532 , and G3583 pineth away [G5743] G2532 : and G2036 I spake [G5627] G4675 to thy G3101 disciples G2443 that G1544 they should cast G846 him G1544 out [G5632] G2532 ; and G2480 they could [G5656] G3756 not.
Mark 9:18 (IGNT) 18 G2532 και And G3699 οπου G302 αν Wheresoever G846 αυτον Him G2638 (G5632) καταλαβη It Seizes G4486 (G5719) ρησσει It Dashes Down G846 αυτον Him; G2532 και And G875 (G5719) αφριζει He Foams, G2532 και And G5149 (G5719) τριζει G3588 τους Gnashes G3599 οδοντας G846 αυτου His Teeth, G2532 και And G3583 (G5743) ξηραινεται Is Withering Away. G2532 και And G2036 (G5627) ειπον G3588 τοις I Spoke G3101 μαθηταις To Disciples G4675 σου Thy G2443 ινα That G846 αυτο It G1544 (G5632) εκβαλωσιν They Might Cast Out, G2532 και G3756 ουκ And G2480 (G5656) ισχυσαν They Had Not Power.