A term used in the firearm community to describe an individual who is obsessed with tactical, paramilitary style firearms and modifications, particularly firearms composed mostly of plastic. Such individuals are usually un-experienced novices who compulsively overpay for weapons and accessories not worth their weight in dog crap because such items looked cool in movies and video games.
Jeff: "Dude check out my new AR-15. Its got quad rails, a flashlight/ laser combination, a dummy grenade launcher, a bayonet, a telescoping stock, and an ACOG scope!"
Matt: "Dude check out my .30/06 Remington 700 with a custom walnut stock and a Leupold scope. I can kill a deer at 500 yards with factory ammo! Can your AR do that?"
Jeff: "Uh, No..."
Matt: "Didn't think so. Admit it. You're a damn MALL NINJA!"