1) Grinding 
• (p. pr. & vb. n.) of Gnash
The grinding together of the teeth as a nonmasticatory function; sometimes associated with emotional tension. ... See: bruxism. ... (05 Mar 2000) ... 
Type: Term Pronunciation: nash′ing Definitions: 1. The grinding together of the teeth as a nonmasticatory function; sometimes associated with emotional tension.
Gnashing: Grinding the teeth. More formally called 'bruxism.' Gnashing, or bruxism, is due to clenching of the teeth other than in chewing and is associated with forceful lateral or protrusive jaw movements. This results in grinding or rubbing the teeth together. Gnashing usually occurs during sleep. It is sometimes so excessive that it damages the...