Heb harak, meaning "to grate the teeth", (Job 16:9; Ps 112:10; La 2:16), denotes rage or sorrow. (See also Ac 7:54; Mr 9:18.)
He has torn me in his wrath and hated me; he has gnashed his teeth at me; my adversary sharpens his eyes against me.
The wicked man sees it and is angry; he gnashes his teeth and melts away; the desire of the wicked will perish!
All your enemies rail against you; they hiss, they gnash their teeth, they cry: "We have swallowed her! Ah, this is the day we longed for; now we have it; we see it!"
And whenever it seizes him, it throws him down, and he foams and grinds his teeth and becomes rigid. So I asked your disciples to cast it out, and they were not able."
Now when they heard these things they were enraged, and they ground their teeth at him.
The Holy Bible, English Standard Version® copyright © 2001 by Crossway Bibles, a publishing ministry of Good News Publishers.