gnash means A sudden snapping of the teeth. Lexicurio rates it Sui generis — a strength score of 86 out of 100.
gnash is pronounced /ˈnæʃ/.
Why “gnash” is a great word
To grind or clench one's teeth together, especially in pain, anger, or frustration. Its etymology reaches back to the Middle English *gnasten*, a word probably of Germanic and onomatopoeic origin that mimics the sound it names; compare Old Norse *gnasta* ('to gnash the teeth') and Danish *gnaske* ('munch, crunch'). Unlike 'grind,' which implies a slow, mechanical attrition, or 'clench,' which describes a silent, muscular tension, to gnash is a sudden, violent, and audible punctuation of suffering. It is the sharp, percussive crack of enamel under duress, the involuntary scrape of a jaw seized by grief, or the furious, gritted prelude to a scream—a bodily rebellion so profound it makes a sound of its own.
Etymology
From Middle English gnasten. Origin unknown; the word is probably either Germanic or onomatopoeic. Compare Old Norse gnastan, Danish gnaske ("munch", "crunch"), German knirschen, German Low German gnirschen, gnörschen (“gnash”), Swedish gnissla (“squeak; gnash”).
noun
- A sudden snapping of the teeth.
verb
- To grind (one's teeth) in pain or in anger.“gnashing your teeth”
- To grind between the teeth.“to gnash the air in fury”
- To clash together violently.“There they were, boiling up in snowy spouts of spray, smiting and gnashing together like the gleaming teeth of hell.”
- To run away.