Gnash is a Flash movie player and Web browser plugin for Firefox, Mozilla, Konqueror, and Opera. Gnash supports many SWF v7 features and ActionScript3 classes. Gnash supports the majority of Flash opcodes up to SWF version 7, and a wide sampling of ActionScript classes for SWF version

Gnash is a project which aims to create a player and browser plugin for the Adobe Flash file format which is free software, replacing the proprietary software niche currently occupied by Adobe Flash Player.

To strike together, as in anger or pain; as, to gnash the teeth.

To grind or strike the teeth together.

grind together, of teeth