Gnaw

Part of speech: verb (v.)

1. To bite, as something hard or tough, which is not readily separated or crushed; to bite off little by little, with effort; to wear or eat away by scraping or continuous biting with the teeth; to nibble at. His bones clean picked; his very bones they gnaw. Dryden.

2. To bite in agony or rage. They gnawed their tongues for pain. Rev. xvi. 10.

3. To corrode; to fret away; to waste.

Part of speech: verb (v.)

To use the teeth in biting; to bite with repeated effort, as in eating or removing with the teethsomething hard, unwiedly, or unmanageable. I might well, like the spaniel, gnaw upon the chain that ties me. Sir P. Sidney.